Beginner collectors and lucky ones, in whose hands were the ancient copper pennies, rubles, money, fifty kopecks, hryvnias or hryvnias, looking at them, they think: how to clear an old copper coin? And, as it turned out, the most common mistake they made was trying to return the coin to its luster. And this greatly reduces its market value! Indeed, in the cleaning process, the main thing is not to overdo it and not deprive the coin of a noble patina, emphasizing its antiquity! Let's try at home to clear the coins and not damage your collection.
What a novice should remember
Of course, it is better if your rarities are cleared by a professional, but he himself is quite capable of coping with this task. To begin with, the numismatist needs to remember that the natural oxides on the ancient copper coin, which have a dark brown, and sometimes black color, are called patina. They can not be deleted! They not only add value to your rarity, but also protect it from the damaging effects of the environment. Consider the patina - if it is even, just wash your coin with warm water and wipe it with a soft cloth.
Citric acid will help in cleaning coins
In cases where the oxide layer is uneven and thick, it must be removed. There are several ways to do this. To get started, it’s worth learning how to clean copper coins with citric acid, which can be purchased at any supermarket.
- Dissolve three parts of acid in seven parts of water, thus obtaining a 30% solution.
- Lower the coin into it and wait no more than 15 minutes.
- As a result of a chemical reaction, purification will occur and the dirt will rise to the surface.
- Do not worry if the coin acquires a pinkish tint - it will change in a few weeks.
- After restoration with acid, the coin must be washed in water with soap containing alkali in order to stop the effect of acid on the metal.
Sometimes for the best result, a repeat of the cleaning process is required.
Can I use laundry soap?
You can also clean the collection in another, more secure way. Numismatists know very well how to clean copper coins with household soap. To do this, plan it on a fine grater and prepare a solution (ratio: 1 part soap and 8 parts water), stirring it thoroughly. Coins are placed in soapy water for two weeks. Periodically, the water is put on fire and heated, not bringing to a boil. The dirt from the coins will begin to disappear during this time, however, sometimes (especially if the oxide layer is thick) you have to make additional efforts to clean (for example, clean them with a soft toothbrush), but most often it is enough to wipe such a coin with a cloth.
By the way, with the help of soap it is best to restore the ancient tsarist and Soviet coins , issued before 1924. And more modern ones can be ruined by such a cleaning!
How to clean copper coins from greens and other stains
In order to save the collection material from stains, it can be boiled over low heat in oil. A good result can be obtained using liquid paraffin, as it has a rather high boiling point. Namely, it is required for successful cleaning.
Coins are kept in boiling oil for 10 minutes, do not forget to just cover the container with a lid to avoid soot. Then they are allowed to cool and washed with soap. Remember to lower the coin for a few minutes in ethanol to remove fat. After this procedure, it can take its rightful place in your collection.
How to clean copper coins from oxidation
If the coin is covered with a dark cherry coating of copper oxide, then it can be removed by immersing the coin in a 15% ammonia solution (a 10% solution of ammonium carbonate, which is less aggressive with respect to copper, is also used instead).
A dark green color indicates the presence of carbon dioxide. This plaque is removed using citric acid (and exactly how it was described above). A less aggressive way is keeping the coins in kefir for 2-3 hours. Do not forget to periodically watch how the process of purification occurs.
Sometimes there are coins that are covered with a pale yellow coating of carbon dioxide lead. This, as a rule, indicates that in its alloy there is a lot of the mentioned metal or that it lay with lead objects for a long time. Such plaque is well removed using a 10% solution of acetic acid.
What to do if rust appears on the coin
If you are concerned about how to clean copper coins from rust, you will have to use a slow-acting reagent. This is Trilon B. The thicker the layer of rust, the longer the coin will have to lie in the reagent.
And some numismatists advise purification using Coca-Cola. This method, although it seems somewhat strange, is nevertheless very effective.
Dry the coins after cleaning
After you managed to clean the copper coins from dirt and oxides, you need to dry them. To do this, it is best to use paper towels folded in several layers, and on top cover your cleaned antiquity with another towel. Use only soft ones for this - you won’t scratch the surface of the coin! By the way, it can also be completely dried in an oven at a temperature of 100 ° C. And in order to prevent and slow down the oxidation processes, periodically rub the collection material with a crumpled newspaper.
What to do if a copper coin has lost a noble patina?
If you still overdo it or for some reason you had to completely clear the coin, you can restore the patina layer by artificially aging the product. True, the peeled coins eventually acquire a patina themselves, but it can look uneven and this greatly spoils the appearance of the collection material. In order to avoid this, the coin is degreased and dipped for 15 seconds in a 10% hyposulfite solution, and after drying it is wiped with a soft cloth. The described operation will help to appear on the subject of antiquity of a smooth and beautiful patina.
Useful Tips
If you still poorly know how to clean copper coins in practice, then it is worth practicing on less valuable products and only then move on to the most expensive copies of your collection. In the case when the coin became unnaturally light as a result of cleaning, put it on the sunny windowsill, where in a week it will get its normal look. True, you must not forget to flip it regularly.
If you come across a coin struck by the so-called "bronze disease", then it is better to give it to a professional restorer. This can be distinguished by oxides on its surface, similar to light green grains. And the coin itself, as a rule, is badly destroyed and crumbles, if picked up.
A few words in the end
We hope that after reading the question of how to clean copper coins at home, it does not seem too complicated for you. But still I want to warn that especially expensive and rare copies of her collection should be given into the hands of a specialist. Otherwise, it may turn out that your rarity is hopelessly ruined.
By the way, toothpaste, paste, salt, baking soda and sand are substances that can cause irreparable damage to the appearance of a collection material. After all, these are abrasive substances that can scratch the surface of a coin and, accordingly, reduce its value.
Good luck with the restoration and collecting!