Cleaning copper coins with folic acid. We clean coins at home: soap, Coca-Cola, citric acid, electrolysis method

In previous articles, the following methods were discussed in detail: soaking in olive oil and, their results can be found by clicking on the corresponding link.

Now it's the turn of chemicals. The most in demand at present are lemongrass, ammonia and Trilon B.

A little bit from chemistry lessons

Let's start with the first substance. Many claim the amazing results of the action of citric acid on the oxides of coins, while others say the opposite - it is an acid in Africa, but it will only kill the find. Let's try to figure out what is true and what is not.

Citric acid belongs to the group of organic acids; it is a solid substance in the form of large transparent crystals, soluble in water and ethyl alcohol. It is classified as a weak acid; it interacts very poorly with most metals, but with their oxides it does very well. This is what the cleaning of copper and silver coins is based on - having destroyed the foci of corrosion, it practically stops working when it reaches pure metal. Those. You don’t have to worry about the relief of the coin, but the patina will fade away if you don’t constantly monitor the process.

Cleaning copper coins

Let's look at the example of Paul I how lemon cleans copper. She underwent preliminary cleaning in soap for two weeks. At the end of the process, it became obvious that further exposure to soap is fraught with the loss of part of the original patina in those places where the field of the coin has been cleared of green oxides.

It was decided to stop soaking and remove the remaining greenery in a more radical way. The choice fell on citric acid. Let me note that this should only be done (cleaned) with low-value coins. There will be experience, then please, but now if you please, learn a little from poop.

Experimental specimen.

First, prepare a solution of the required concentration: water 35-50g C - 100ml, citric acid 1/3 tsp. The ratio is given approximately, over time you will determine the desired proportion yourself.

Then we pour the solution into a suitable container, put a coin in it and begin to remove the green oxides using toothpicks and cotton swabs. Using chopsticks, we remove the easily coming off greenery, and clean out the hard growths and small details of the relief with sharp toothpicks.

The process of interaction between acid and oxides, even in such a small concentration, is quite intense, so we do everything quickly. In just a few seconds the greenery will begin to peel off; difficult areas will take a little longer to work on.

As soon as the field of the coin becomes clean on both sides, immediately remove it and rinse it under running warm water.

If in any place the growth is difficult to give in, you should not keep the coin in the solution, because it will damage the original patina - the copper will be covered with pink spots. Therefore, we take it out, wash it and deal with this area separately, for example, by applying cotton swabs moistened with lemon to it.

If this does not help, then only mechanical clearing with a scraper.

The result of treating a copper coin with citric acid.

Overall, I think the two-room apartment was cleaned well. The only drawback is the lightening of the patina on the reverse of the coin, in the area of ​​the letter O, in the word kopek. The reason is that it had to be taken out a little earlier; such a delay was associated with the removal of a difficult-to-grow growth in the lower right curl of the monogram.

Some facts from respected experts:

• Use acid to clean low-value copper coins, or in exceptional cases.
• Citric acid best cleans copper carbonate - light (dark) green oxides.
• During the cleaning process, it is better to replace the solution with a new one, then there is less chance of the formation of reduced copper on the surface of the coin in the form of pink spots.
• It is better not to touch a find with deep or even through corrosion.

Silver cleaning

Citric acid is considered one of the most, and perhaps the most the best way cleaning silver coins. It is excellent for both pure metal and low-grade metal (bilons).

There can be three options for its use:

1) Soaking in solution.
2) Local cleaning.
3) Boiling.

The first method is carried out in exactly the same way as in the case of copper: the coin is filled with an acid solution and then cleaned of dirt deposits and oxides with dental chopsticks.

The second method is gentle and is used to remove small contaminants. Its essence is as follows: only a small area of ​​the coin’s field is subjected to treatment, periodically adding drops of the solution and using three sticks until the stain completely disappears.

The third method is the most radical, but at the same time the most effective (in advanced cases).

Cleaning is carried out by boiling the coin in a solution of citric acid. This removes strong or very stubborn stains. This is especially often done with low-grade money - small change money, from the end of the 19th century to the 2000s of the last century.

For cleaning, take a suitable enameled iron vessel, in this case a mug. Pour water and add lemon at the rate indicated for copper.

We put the coin(s) there, put it all on the fire and boil. The process requires your continuous presence. As the temperature rises, it will be noticeable how the acid reacts with metal oxides. From time to time we take out the coins with a wooden spatula or special tweezers and try to clean them with cotton swabs and toothpicks; if the result is not impressive, we throw them back. And so on until the silver becomes pure.

You shouldn’t pore over the mug too much, the coin won’t dissolve, but you shouldn’t leave everything to chance; overexposure can threaten to damage the relief.

At the end of the process, be sure to wash each one under running water.

Most often, citric acid copes with its task, only in rare cases it turns out to be powerless. But you shouldn’t get carried away with it if gentle, albeit longer, methods are possible.

I apologize for the bad photos, I will take and post better ones in the future.

To become an experienced and professional numismatist, you need to be able to understand many things. The fact is that numismatics includes many subtleties and details that are important when collecting rare and valuable items.

Regardless of the experience of a numismatist, every collector should know how to clean copper coins at home. This process is simple, but has its own nuances. Cleaning metal products is necessary if coins have a certain level of dirt, oxidation or plaque. To give the collection a decent look, you need to protect the metal surface with a layer of patina. Then the specimens acquire shine, and the engraving details are clearly visible to the naked eye.

Now the topic of how to clean copper coins at home is very relevant among numismatists. The fact is that the opinions of some experts in this case differ. Some say that substances can destroy appearance metal products, while others, on the contrary, claim the opposite. If you use untested methods and dubious detergents, then there is indeed a chance of damaging the appearance of the coins. In this case, you need to take a responsible approach to restore the original appearance of the products. It’s also worth thinking in advance about how to clean a copper coin at home.

During the years of the USSR, a huge number of different coins. Several dozen factories operated throughout the country, diligently producing metal products for the population. More than a decade has passed since their release, so their appearance has changed slightly. The value of such coins instantly drops in the market if they are not properly cared for.

Each copy that was released in the Soviet Union has its own history. To preserve the memory of bygone years, you need to know how to clean a copper coin at home.

Experts do not recommend using chemical compounds without certain skills. It is worth noting that suitable drugs are not so easy to find. But there is an opportunity to make your own mixture at home: ammonia, soda and toothpaste. This composition effectively and quickly copes with contaminants. In addition, this mixture can be prepared in large quantities and pack in a well-protected container. The mixture must be stored covered so that the beneficial properties do not evaporate. After applying the composition to the surface of the coin, it is necessary to rub it with a brush and rinse with warm water. At the end of the procedure, the coins must dry thoroughly.

You can use water and baking soda to remove varying degrees of contaminants. The mixture must be poured into a clean container and a coin placed there for two hours. During this time, the surface will be cleared of dirt and become shiny. Then you need to wash all metal products and dry them.

Also, some numismatists use another effective method, which is as follows: one teaspoon of citric acid, a glass of warm water. This composition needs to be stirred well, and then a metal product should be placed there for a minute. Then you need to quickly take out the coin and wipe it with a dry cloth. It is important to remember that the coin should not be left in the solution for a long time, otherwise it may deteriorate. In this case, the specimen will completely lose its shine.

Copper exhibits

How to clean copper coins? Even from such metal, you can clean the surface of products at home. At the same time, everything can be done without damage.

You should adhere to the following instructions:

1. First you need to prepare a solution consisting of laundry soap. Before this, you need to cut the soap into small shavings and put it in a container with boiling water. Then you need to wait until the soap is completely dissolved in the water. And only then can you put metal products in a container for two days. From time to time it is worth cleaning the surface of the coins with a brush. Upon completion of the procedure, each coin is dried and washed. If necessary, you can repeat the procedure. As a result, the oxides should disappear from the specimens, turning the coins into a sparkling collection.
2. How to clean copper coins at home? It's very simple, just take a soap solution and add soda to speed up the process. It is worth noting that you should first mix soda with water. After these steps, each coin must be lubricated with alcohol and Vaseline for shine. In this way, products can be protected from contamination and oxidation.
3. Renewing the appearance of metal products can be done using citric acid. To do this, you will need to immerse the coins in the solution for half an hour, and then wipe them dry with a soft cloth. It is possible that the metal may acquire a pink tint, but after thirty days it will disappear.
4. How to clean copper coins at home to get rid of the problem quickly and effectively? You can dip coins in boiled Vaseline oil for half an hour. In general, you need to boil metal products until they are completely clean. Then, if necessary, rinse again in ethyl alcohol.
5. If the specimens are in poor condition, they must be handled very carefully. In this case, you can use caustic soda, having previously dissolved it in water. To avoid getting burned, you need to prepare for cleaning by wearing special gloves. To work, you will also need tweezers, with which you will need to dip coins in the solution. It is worth remembering that not all types of coins can withstand strong alkali. If during the cleaning process the coins begin to turn blue or green, then you need to interrupt this method.

Now every numismatist knows how to clean a copper coin at home. The main thing is to follow certain instructions, then the coins will be in perfect order. And then there will be no problem with how to clean copper coins at home?

Bronze exhibits

Most methods for cleaning bronze coins from dirt are similar to methods for cleaning copper products. It is also possible to use citric acid and soda. The following composition is acceptable for use: Trilon, ammonia, water and toothpaste. Properly used substances will help quickly get rid of darkening on specimens.

It is not recommended to use nitric or sulfuric acid. In this case, the acid will only be useful when cleaning inexpensive coins that are in poor condition. At the end, the surface can be smeared with sulfur ointment for shine. The procedure includes the following steps: Vaseline ointment and sulfur ointment are applied to the coin and all this is smeared over the entire surface using a toothbrush. Finally, rinse the bronze items with warm water. Thus, the coin is covered with a protective layer that protects the material from oxidation. Residues from the oil can be washed off with running water.

Cleaning antique coins

If you have old coins in your collection, they should be treated with vinegar and toothpaste. To ensure that the composition lies evenly on the surface of the coin, you must apply it carefully with a toothbrush. It is better to use this tool in a circular motion to remove plaque on the surface. Experts advise immersing the product in a container with vinegar for just about twenty minutes. You should not leave coins in the solution for a long time, otherwise the coins will become unusable. At the end of the procedure, you need to rinse them thoroughly in water.

As a rule, pieces of earth get stuck in coins of the imperial period, which negatively affect the appearance of the products. Experts advise boiling exhibits in water and soda. But before the process you should prepare: one tablespoon of soda per 200-300 ml of water. You need to boil for no more than 30 minutes. Although this procedure can be repeated until maximum results are achieved.

If it comes to silver coins, then it is possible to use ammonia with water. The coins are placed in the liquid for sixty minutes. It is worth noting that if you don’t have ammonia at home, it doesn’t matter, because you can always replace it with soda.

It is important to remember that after each procedure, all specimens must be thoroughly dried. The fact is that the appearance of the collection depends on this.

Everyone is showing interest in numismatics these days. larger number people. The hunt for rare coins is gaining momentum. Unfortunately, almost any metal can be oxidized, which negatively affects the appearance of the product. Cleaning coins - the only way cope with this problem. The tips given in the article will help you do this quickly and efficiently.

There are a large number of techniques that can be used to remove contaminants. Cleaning coins at home is a task that anyone can handle. Be sure to take into account the recommendations below.

• The cleaning method must be chosen depending on what alloy the affected specimen is made from. Otherwise, there is a danger of irreversibly damaging the coin rather than saving it.
• It is advisable to avoid products that contain abrasive particles. There is a high probability that their use will result in scratches on the surface of the coin.
• Cleaning coins with concentrated acids is also not recommended. First of all, this applies to copper specimens.
• Removing the patina may reduce the value of the coin. For some products it serves as decoration.
• It is advisable to check the selected product before the procedure. Experiments can be carried out on products that are made of similar material.

Silver

How to restore the original beauty of silver coins? Cleaning with a solution of ammonia and baking soda is an excellent choice.

• You need to dissolve two tablespoons of soda in a glass of hot water. You can also add a few drops of dish soap. The product is placed in the resulting mixture for approximately eight hours. The coin is then thoroughly washed and dried.
• In a glass of hot water you need to add 30 ml of hydrogen peroxide and a teaspoon of ammonia. The affected specimen must be kept in this solution for about 15 minutes. The mixture is then diluted and drained until the silver is in clean water. Next, the coin is thoroughly washed and wiped with a soft cloth.

If the choice is made in favor of the second method, extreme caution must be exercised. The coin must be turned over without removing it from the liquid. There is a possibility that an oxidation process will occur in air. In this case, the metal will be damaged.

Copper

How to clean copper coins at home? These products are famous for their capriciousness, so returning them to their original beauty must be done with care.

• Vaseline oil. The affected specimen must be boiled in it until the contaminants disappear. The final part of the work is to rinse the coin in alcohol and dry it with a soft cloth.
• Hydrogen peroxide. This product will help restore the lost shine to the product. Dissolve 30 ml of peroxide in 200 ml of water, and then add a teaspoon of ammonia. The coin should be kept in this mixture for no more than 15 minutes.
• Neutral soap (laundry, baby). It must be grated on a coarse grater. The resulting porridge should be coated on both sides of the damaged specimen. The product will have to be left in this form for a long time, which is the main disadvantage of this gentle method of cleaning copper coins. From time to time it is necessary to remove the specimen and clean it under running water with a soft brush. This will remove softened contaminants. The procedure continues until the desired result is achieved.

Bimetallic

When creating some coins, for example, commemorative coins, two different metals are used. The central part is made of silver or steel, and gold, copper or various alloys are used for the edging. How to clean such a product?

• Dishwashing liquid. You can use, for example, “Fairy”. Dissolve one tablespoon of the product in a liter of water and mix thoroughly. The coins are kept in the liquid for about an hour, then removed and wiped with a flannel rag. Dishwashing detergent shows excellent results when dealing with minor stains.
• Toothpaste. Apply a pea-sized amount of regular paste to a soft-bristled brush. The affected specimen must be rubbed carefully; strong pressure is not required. Cleaning of coins ends with rinsing in water.
• GOI paste. This product includes small abrasive particles, which allows it to effectively combat dirt and oxides. The paste should only be used for inexpensive coins, as there is still a danger of damaging the product.
• Formic acid. This product will help restore the specimen to its original shine. You need to immerse the coin that needs cleaning in a 14% solution for about five minutes, and then polish it. Instead of formic acid, it is allowed to use alcohol.

Cupronickel

Cupronickel is also capable of oxidizing and turning black, and has a similar composition to noble metals. The methods discussed below are suitable for cleaning coins at home.

• Ash. With its help, you can quickly and effectively rid the product of patina. The affected specimen is dipped in water, then cigarette ash is applied to it. After about 20 minutes, the coin needs to be rinsed.
• Dish powder. This product is applied to the product after wetting it with water. It is necessary to treat the surface of the damaged specimen with a sponge and wait for some time. The coin is then washed in water.

Brass

What product should I choose to clean coins made from a copper-zinc alloy? Such money is not particularly susceptible to corrosion, but still needs cleaning from time to time.

• Oxalic acid. This product can be purchased in a store. With its help it is easy to remove plaque, it shows good results even in the fight against old stains. The coins need to be immersed in acid for about ten minutes. Be sure to thoroughly rinse the money with water after finishing the cleaning procedure.
• Trilon-B. This product must be dissolved in clean water, maintaining a ratio of 1 to 10. Then the coin is dipped into the resulting solution. She shouldn't be there all the time. From time to time, the specimen must be washed in running water and inspected. Soaking is repeated until the desired result is achieved.
• Other means. What other ways to clean coins are there? Citric acid, Coca-Cola, and a thick soap solution will help restore your products to their original beauty.

Aluminum bronze

Which tools should be preferred in this case? Coins made from this material can be cleaned using the same methods that are suitable for copper coins. There are other effective methods.

• Coca-Cola. This popular drink is not only drinkable, it has also gained a reputation as a good stain remover. The main disadvantage of this method is the long wait for the result. You will have to keep the coins in a glass of Coca-Cola for about a week. Then they must be rinsed with clean water.
• Plumbing cleaner. The affected specimen must be immersed in such a solution for no more than a couple of minutes. It is then cleaned using running water.

USSR anniversary coins

There are specimens that need special care. For example, how to regain lost attractiveness commemorative coins USSR at home? Cleaning in this case is done using an ordinary eraser. This must be done carefully so as not to damage the drawing.

You need to rub the dry surface with an elastic band until the plaque disappears. This method is suitable for adding shine to any alloy products.

Universal remedy

What methods are suitable for bringing any coins back to normal? There is a universal remedy that contains several ingredients. It will help cope with rust, green deposits and other oxides.

• You need to mix 25 ml of soda and soap solution. 25 ml of ammonia and 75 ml of toothpaste are added to the resulting mixture.
• All specimens that need to be cleaned must be immersed in the finished product. There they remain until the goal is achieved. Periodically, coins should be removed, wiped with a toothbrush and inspected. At the end of the procedure they are washed with water.

Electrolysis

Working with electrical devices requires knowledge of safety precautions. We also must not forget that their use significantly increases the likelihood of damage to specimens. Cleaning coins by electrolysis is carried out in a well-ventilated and lit area. You should definitely take care to protect your hands and eyes.

• You need to prepare a power supply with a voltage of 6-12 V. Next, the plugs are cut off, the wires are cut into two parts. Then you should clean the ends and attach the copper wires to the clamps.
• The plastic container is filled with saline solution. It is easy to prepare by placing a tablespoon of salt in a liter of water.
• The power supply is connected to the network, the clamps are lowered into the resulting solution. The “+” terminal should be connected to the coin, on which a hissing sound will be heard. The entire procedure will take no more than ten minutes.

Vinegar

What other methods can be used? Vinegar is a product that is suitable for bringing inexpensive specimens into proper shape. It must be remembered that the solution can corrode the surface of the product and change its color. In addition, it is believed that after such a procedure the coin will deteriorate faster.

• Any specimen that needs cleaning can be immersed in a solution of 10% vinegar for a day. This is the easiest way.
• You can also prepare a mixture of vinegar and salt. Approximately 5 g of salt must be mixed with a quarter tablespoon of vinegar. You need to stir the mixture until the salt dissolves. Then coins are dropped into the resulting solution. This must be done so that the copies lie separately from each other. Products are soaked in the solution for no more than five minutes. If dirt remains, you can further treat them with a brush. Next, the specimens should be carefully washed in running water.

Cleaning coins with vinegar - dangerous choice. Its use can negatively affect the appearance and condition of products made of silver, copper, aluminum, and lead.

Machining

What other options are available? Mechanical cleaning coins are used to remove surface deposits. We can talk about sand, earth, individual tubercles of corrosion. To carry out the procedure, various brushes are required (brass, bristle, glass fiber). You will also need dental burs of different sizes and scalpels. These devices must be used with the utmost caution. If used improperly, there is a danger of causing scratches that will distort images, inscriptions, and so on.

• The damaged specimen must be kept in distilled water for about an hour. This is necessary in order to desalt the product and get rid of dried dirt.
• Next comes the impregnation of the coin with synthetic resin. This is required to strengthen the noble patina and prevent damage.
• Then you can proceed directly to cleaning the instruments. This work is very painstaking and time-consuming; it will require a huge amount of patience. The master can clean some instances within a month or two.

Mechanical cleaning is a method that is more suitable for professionals. Hobbyists risk hopelessly damaging the coin. Therefore, it is recommended to develop appropriate skills on specimens that are not of particular value.

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If you are interested in searching antique coins, you have probably encountered the fact that sometimes found coins simply cannot be identified, and in order to find out at least the denomination of the coin, it needs to be cleaned. Well, this is in the most difficult case. Often coins need cleaning, because they have a green coating, various salts and just a centuries-old layer of dirt. So I decided to summarize all the ways to clean coins. In this article we will look at all the methods cleaning copper coins. So how do you clean copper coins?

First of all, I’ll warn you right away that if the coin is quite rare, then there’s absolutely no point in cleaning it yourself. For me personally rare coin- this costs more than 3,000 rubles. Agree, it will be very disappointing if you ruin such a coin by using the wrong cleaning method. So if the coin is rare, it’s better not to clean it yourself, but to sell it straight away. Whoever buys it will clean it himself or give it to restorers for cleaning. Also look carefully at the patina - if the patina is smooth, then you should not clean such a coin with anything, just rinse it in warm water and wipe it with a soft cloth. Patina reliably protects the coin from corrosion.

Cleaning copper coins with ammonia.
I myself use ammonia very often, but only very carefully. You need to remember that ammonia changes the color of copper and when exposed to ammonia, the coin can turn completely red, which, you see, is not very beautiful. So you need to clean it with ammonia carefully; if you immerse coins completely in ammonia, then only for a short time and constantly monitor the process. Better yet, put the coin in for 5-10 seconds, then take it out and wipe it with a soft cloth.

Ammonia, like Trilon B, changes the color of the coin. But the color of a coin can be restored if the coin is artificially aged, or as they also say, apply patina to a coin. Although cleaned coins will acquire a patina on their own, it may be uneven and not always natural. So if this happens, then you can try to patent the copper coin yourself. This is done this way - after cleaning the coin, degrease it and immerse it in a 10 percent hyposulfite solution for 15 seconds. When the coins are dry, wipe them with a soft cloth. The patina will lie smooth and beautiful.

Well, you've arrived from the cops and you have a couple of copper coins at your disposal that need cleaning. The most important thing when cleaning is to choose the right method, but sometimes this is not so easy. So first examine the coin carefully with a magnifying glass. If there are oxides on it and it is difficult to see letters and numbers, then first place such a coin in a vessel with distilled water. We take a half-ruble, cut off the top, put some kind of coin stand inside, preferably one with holes. Place the coin on the stand and fill it with distilled water. It is advisable to close the top too. Leave for 2-3 days. Distilled water softens all corrosion, so after soaking in water, we proceed to mechanical cleaning of the coin. For this we need toothpicks. We carefully pick off the growths on the coin, doing everything very carefully. So we pick at it with a toothpick and periodically wash off what we picked off. The first stage of cleaning copper coins has been completed; most of the oxides have been removed.

Next, you can dip the coin in soap; the most popular way to clean copper coins is by cleaning with soap. To do this, take ordinary laundry soap and rub it on a coarse grater into a shallow container. Then pour all the flakes with warm water until a thick paste forms.
Next, we lower our coins into this mass and leave it for a long time. About once a week we take out the coins and clean them with a soft toothbrush. As soon as a green mass appears in the container, it’s time to work with a toothbrush. Cleaning copper coins with soap sometimes produces amazing results. As a rule, most copper coins are cleaned with soap; this is the most humane way. If you come from a dig, you can immediately soak all the coins in soap and periodically brush them with a toothbrush, removing green deposits, dirt and even oxides. After all, soap is a weak alkali and has an excellent effect on oxides. So if you don’t know how to clean coins yourself, just soak them in soap, it won’t make things worse. But this method is only suitable for ancient copper royal coins. If you try to clean up the advice this way, the result may not please you. I've ruined a lot myself Soviet coins. So soap is for ancient royal coins. Well, if the advice is, then until 1924, they are heavy copper, also easy to clean. By the way, to make the soap react faster, you can heat the soap solution, the reaction will noticeably speed up.

It is also worth noting this method of cleaning copper coins: boiling in Vaseline oil. You can buy this oil at any pharmacy. Next, pour the oil into an iron container, put copper coins in it and put it on low heat. Be sure to close the lid, otherwise the soot will be such that mom don’t worry. When the oil comes to a boil, wait 10 minutes and then remove from heat. Be sure to let the oil cool, take out the coins and brush with a soft toothbrush in soapy water. As a rule, all the soot and blackness are erased with a brush, as a result the coin becomes smooth and beautiful. But of course, sometimes it turns out differently. Once we ruined several coins this way because they only had patina, the core of the coin was simply missing. And it just boiled over like porridge. So before cooking, carefully inspect the coin. But as a method of cleaning copper coins, cooking in oil has its place. Try it, experiment. Only on unnecessary killed coins))

Cleaning copper coins with citric acid.
Some people use citric acid. But this is already aggressive method and requires constant monitoring. You need to clean it very carefully with citric acid; it can instantly destroy the entire design and relief of the coin if you overexpose the coin. So I don’t use lemon juice, but people do and the results are good.

Also works great when cleaning copper coins. drug Trilon B. But here you need to be careful and correctly determine the thickness of the oxide layer. The thicker the oxide layer, the longer the exposure time to Trilon B. If you clean your copper coins properly, the quality of your coins can be amazingly improved. But it is also worth keeping in mind that when cleaning with Trilon, all the shells and small cracks on the coin may open. So if the coin looks good in appearance, then trilon will help to further improve the appearance of the coin.

Cleaning copper coins with kefir.
Another great method that works great for freshly dug coins. Efficiency equal to soap. Kefir is a very weak acid, so there is no need to worry that the coin will deteriorate. Take kefir and fill the copper coin completely. Now sometimes you look - once every half hour - to see what’s there and how. As a rule, greens immediately begin to appear in kefir, and the oxides dissolve. The method is great for copper coins. Usually 2-3 hours are enough to completely dissolve the green oxides on the coin.

Well, another good way to clean copper coins is olive oil. But I’ll immediately warn you that this method is the longest, but also the safest. Just take the copper coin that... you need to clean it and put it in olive oil for a couple of months. After 2 months, you take it out, work a little with a soft toothbrush and go back. They clean it this way for about 4-5 months. The coins are obtained as if from a treasure, in collectible condition. So if you have nowhere to hurry, dip it in olive oil for six months))

After cleaning, copper coins can be wiped with wax or oil. This way they become marketable, so you can sell them well at auctions.

Let us introduce you to safe ways to clean coins from an archaeological metal restorer with many years of experience in the Hermitage. An article about these cleaning methods was published in the book “The Past of Our Motherland in Numismatic Monuments.” The author of the useful material is Hermitage employee O. V. Vasilyeva. Let's move on to the most useful excerpts from the text.

Clearing Coins- one of the responsible types of restoration, it is important for their study, dating, identification and storage.

Ancient coins made of silver and copper alloys, discovered in treasures or other archaeological excavations, most often arrive at the restoration workshop heavily corroded, sometimes completely mineralized. Under the influence of water and salts, copper is destroyed in the soil with the formation of green carbonates and chlorides, red cuprous oxide and black oxide. In the corrosive layers on bronze coins compounds of tin and lead are found. Silver-copper alloy coins are often coated with copper corrosion products. Sometimes silver, under the influence of chloride salts, turns into gray-violet chloride, horny silver. In air, copper alloys darken due to oxidation, and silver - as a result of the formation of sulfide.

Restorers always treat the restoration of numismatic monuments with great caution. In particular, they do right choice reagent necessary for cleaning from corrosion, since a reagent successfully used for some coins may be unsuitable for others and will lead to their destruction or distortion of their appearance. It is advisable to achieve the preservation of a noble patina, a kind of certificate of antiquity of objects.

So, when starting to clean coins, you should first of all find out what metal they are made of, whether they have a metal core, to what extent it has been preserved, and what salts the coins are coated with.

Cuprous chloride

It is important, for example, to determine the presence of copper chloride in corrosion crusts on copper coins, which in humid atmospheric conditions causes an active corrosion process - “bronze disease”. To detect copper chloride, a humidification chamber is used: a glass vessel is filled with water to approximately 1/7 of the volume; A perforated plate made of plastic, plexiglass or porcelain is placed above the water, on which coins with a corrosive layer are placed. The container is tightly closed with a lid. It is left in this state for 1-3 days.

The effect of the humidification chamber is to accelerate processes occurring under the influence of air humidity, which helps to identify areas of active corrosion and makes it possible to choose more successful cleaning methods. Keeping coins in the chamber helps loosen the surface layer of oxides, facilitating further cleaning operations. If there is copper chloride in the corrosion layer, droplets of liquid, colorless or slightly greenish, appear on the surface of the coins. Otherwise, the droplets do not protrude: copper carbonate, copper oxide and copper oxide are stable in humid conditions (horny silver on silver coins also stable). And if copper chloride is detected, it must be removed from the deepest pores and very thoroughly.

Stuck

Often during excavations, coins are found boiled, forming a shapeless mass. We do not recommend separating such coins by heating them and immersing them in cold water. To avoid loss, such a lump should be placed in a 5-10% sodium hydroxide solution and heated to 30-50°C. After this, the coins can be separated from each other, determine the condition of each of them and begin cleaning.

Cleaning methods

The main methods of clearing coins are mechanical, chemical and electrochemical. During restoration, a combination of mechanical methods with others is practiced.

Mechanical treatment consists of removing surface layers: earth, sand and individual corrosion tubercles. It is performed using various brushes, scalpels and dental burs of various sizes. But if used roughly, it is easy to cause scratches that will distort the inscription, images, etc.

• Copper coins

Chemical methods, in combination with mechanical methods, clean coins that are covered with a thick layer of corrosion products, but have retained the metal base, as well as coins made of gold and silver.

To remove the cherry-red coating of cuprous oxide from copper coins, you should immerse the coins in a 5-15% ammonia solution, but so that they are completely immersed in the solution, because in contact with air the effect of ammonia on the metal will be destructive.

If copper coins are coated with salts consisting of copper carbonate (dark green), these deposits should be removed with a 5-10% citric acid solution. It slowly dissolves copper salts and oxides and does not dissolve metallic copper.

There are also copper coins coated with a yellowish-pale coating of lead carbonate. This suggests that the alloy of the coins themselves contains a lot of lead or they were lying in the ground with lead objects. To remove such deposits, you should use a 10% solution of acetic acid, which easily dissolves lead carbonate.

The restorer often has to deal with coins that are completely mineralized, which cannot always be preserved. The success of the treatment depends to a large extent on which compounds have replaced the metal through complex mineralization processes. First, carefully remove surface deposits. If in this way it is possible to identify this or that ornament, inscription, etc., then this should be limited. If mechanical processing does not open the coin, use a 5% solution of caustic soda or ammonium carbonate.

Attention! Since the degree of preservation of coins varies, it is difficult to give recommendations regarding the time they spend in one or another reagent. Therefore, periodically removing coins from the solution, you should gradually remove the softened layers mechanically, thereby speeding up the cleaning process.

• Silver coins

Silver coins are cleaned primarily by chemical means. Such cleaning is reduced to removing oxides and salts of other metals, mainly copper compounds, from the surface. Copper connections on silver coins are identifiable by their green color. To remove them, place the coin in a glass vessel or porcelain cup and fill it with a 5% sulfuric acid solution. To speed up the process, you can clean with a heated solution, removing the coin from time to time, rinsing it with water (preferably running water), then removing the mechanically softened salts with brushes. You can also use a 5-10% solution of formic acid, preferably heated to 50-70° - the hotter the solution, the stronger its effect.

Formations of violet-gray horny silver are exceptionally soft. Such coins often lack a metal core, and during cleaning the possibility of their complete loss cannot be ruled out. But if the horny silver crust is not too thick, the coin can be immersed in a 5-10% ammonia solution. In these solutions, the horny silver softens, after which it is carefully removed mechanically.

A brass brush is a restorer's tool.

For coins that retain a metal core but have very dense, hard, thick oxides, as well as for fragile coins, the electrochemical reduction method can be applied. This method does not require special equipment. For electrochemical processes, zinc and aluminum are usually used. Practice has shown that for cleaning coins it is best to use plates made of sheet zinc or aluminum, with holes punched in them (like a grater). Formic acid of 5-10% concentration is taken as an electrolyte. A zinc or aluminum plate is placed at the bottom of the glass vessel. Several coins are laid out on the grated surface of the plate, which are covered with the grated surface of another similar plate. After this, the vessel is filled with the prepared solution so that the coins with the plates are completely hidden.

Processing using this method should be carried out especially carefully and carefully, with frequent monitoring of the progress of the process. Mechanically removing the restored and softened corrosion products, inspect the coin through a magnifying glass to determine the degree of its cleaning.

Note that gold and new coins that have not been in the ground, but have only been in circulation for a long time, can be cleaned easily and quickly. It is necessary to remove fatty substances from them with acetone, gasoline or alcohol and dip them in a 5-10% solution of citric or formic acid.

After cleaning

After cleaning the coins in one way or another, they should be thoroughly washed (boiled) in several changes of boiling distilled water until the water reacts neutrally according to a universal indicator. After washing, the coins are dried in acetone, then in alcohol for 30-60 minutes. For this purpose, you can also use a thermostat (a special drying cabinet), keeping coins in it for no more than two hours at a temperature not exceeding 100 ° C.

If copper coins have an unpleasant shine after cleaning, you can artificially create a light to dark brown patina. To do this, you need to take 50 g of copper sulfate and 5 g of potassium permanganate per liter of distilled water. Place coins in the prepared solution, heated to 70-80°, and hold until the desired shade is obtained.

After drying, the coins must be preserved with a protective coating - paraffin or synthetic resins. For this, we can recommend 5% solutions of polybutyl methacrylate in acetone, toluene or xylene and polyvinyl butyral in alcohol or a mixture of alcohol and benzene (1: 1).

After conservation, it is necessary to store coins and medals not in piles, but in separate cells of albums or in trays with compartments.

Additional information about metal restoration can be found in the books by M. V. Farmakovsky “Conservation and Restoration of Museum Collections” and H. D. Plenderlis “Conservation of Antiquities and Works of Art.”

Well, about more modern methods of cleaning coins using effective means, read on “MDRegion” and look at our channel on YouTube.