One of the problems in numismatics is how to preserve the look of your collection so that rare, hard-to-obtain specimens please the eye for a long time. All coins, regardless of whether they are made of precious metals, copper, aluminum or nickel, require cleaning. You can hold such an event at home yourself. The rules for removing corrosion, oxides, grease depend primarily on the alloy from which the coin is made. We will figure out how to clean a copper coin at home.
Before starting the cleaning itself, it is necessary to carefully study all its aspects. After all, incorrectly carried out, it can not only not return to its original form, but also harm the product. One of the harmful layers on a copper coin is a layer of green copper, or coppers. This is a layer of oxide of copper acetate, which appears on the coin under the influence of acetic acid vapor when interacting with oxygen.
Cleaning copper coins
The easiest way is to treat the coin with a 5-10% solution of acetic acid. Table vinegar is also suitable for these purposes. Depending on the initial condition, coins can be in solution from several minutes to several hours. Periodically, they must be removed, turned over and wiped.
Another way to give coins from copper their original appearance is to treat them with a solution of laundry soap. In order to prepare such a solution, the soap chips are poured with boiling water. You can use a plastic container to prepare this product.
When dissolved, the soap should turn into a jelly-like substance. Coins must be placed there for two days. Then take a soft brush and rinse thoroughly under water, dry at the end. Some oxides will not be able to be removed immediately, but such a procedure is considered gentle, it can be repeated as much as you like.
There is a faster way. To do this, add soda dissolved in water to a soap solution. Then rinse the coin so that there are no traces on it.
If it is necessary to clean the coin from the oxide layer, it is best to use slow-acting copper cleaning agents. One of these is Trilon B.
You can prepare a solution of citric acid. For 70 milliliters of water, 30 grams of powder is taken. Most often, citric acid is sold in bags of 10 grams, so you need three of these packages. When the coin is lowered into this solution, the reaction begins, it will continue until the patina completely disappears, about 5-10 minutes. Next, the coin is removed clean, without damage, since citric acid is too weak for this. It happens that this time is not enough, then you can add more acid or take out a coin from time to time and wipe it with a brush.
For copper coins, the boiling method in liquid paraffin is also sometimes used. You need to boil until the coin is completely cleared, and then wipe it with alcohol.
For coins in very poor condition, a solution of sodium hydroxide or caustic soda is used. The solution is prepared in cold water. First, take a low concentration, then increase. Place the product for a few minutes, then rinse thoroughly.
Cilit is a good rust cleaner for copper coin cleaning. To clean the product with it, apply it to a metal surface and wipe with a sponge. Then rinse with water.
You can use an ordinary lemon, for this you need to cut it in half and put a coin there for a quarter of an hour. Then get out and brush. Rinse well in water and wipe dry.
Prepare such a cleanser: mix the salt with flour and add a drop of vinegar. The coin is rubbed with this tool and left for a while. Rinse it with running water.
Copper can be easily cleaned by digestion in vinegar. For this, acetic acid is added to boiling water, the concentration should be less than 25%. Additionally, add two tablespoons of salt and put a coin there. When cooling is complete, remove and clean with a soft brush. If the coins touch each other during cleaning, the place where they touch may remain uncleaned. Be careful when handling acid to avoid poisoning it with fumes.
You can use toothpowder or whitening paste to clean coins. Rub the product, the movements should be active. Wipe the coins and evaluate if they are sufficiently cleaned, if the coating remains, it is recommended to repeat the procedure.
Cleaning copper coins in soapy water
Ammonia also copes well with copper and black. Ammonia will react with compounds that give such a coating, after which they can be washed off with a soap solution.
White plaque can appear on coins in the ligature of which zinc is present. To clean such a coin, you can simply take distilled water and hold the coin in it for several days.
You can use a jewelry cleaner or take a coin to a jewelry workshop, where, using a specialized copper coin cleaner, they can do just fine with any kind of plaque.
It is not always necessary to clean copper products. In addition to corrosion and grease, they can be covered with a patina. Patina is a layer of oxides that forms under the influence of oxygen, salts, acids and carbon. Patina is considered beautiful and valuable, it gives the coin a noble appearance and can have different colors, from brown to greenish black.
If the product is covered with a uniform layer of patina, then it is not recommended to clean it, as it may lose its value.
How to clean copper coins is impossible?
In order for the coin not to lose its appearance and not erase the picture, it is impossible to clean copper coins at home:
- Abrasive powders and tools: this effect can damage the patina and leave traces of damage. It can be household chemicals, sandpaper, a metal brush, or a brush with hard bristles.
- Use concentrates of acetic, hydrochloric, sulfuric or nitric acids: the minting pattern can be damaged.
- You should also not use a solution of ferric chloride. Ferric chloride is the salt used to etch circuit boards, it reacts, literally corroding copper.
- Expose copper coins to high temperatures. The metal can not only melt, but also lose its structure after cooling and begin to crumble.
Drying the peeled coins is a must. If this is not done, they will be oxidized, their appearance will deteriorate. You can do this this way: place the coins after washing on a paper towel folded several times and get wet. You can wipe the product with a cloth, but it is very important that it does not leave marks. Cotton fabric is best. A drying cabinet is also used, but it is very important to remember that the temperature should be low, not more than 100 degrees.
The peeled coins look unnatural, as they have no patina. Over time, it appears, although it may lie unevenly. There is a way to avoid this: after cleaning, the coin can be aged.
For this, the substance used in the dark laboratories is hyposulfite. The coin is dipped in a 10% solution for 10-15 minutes, after which it is taken out and wiped dry. For safety, a nickel-copper coin can be opened with varnish. Another option is to lubricate the coin with alcohol and liquid paraffin, which will also protect it from further exposure.
How to store coins after cleaning?
To ensure that the coins are not oxidized and do not need frequent cleaning, they must be stored correctly. They should be kept in a dry place, protected from direct sunlight. There are several storage methods commonly used by collectors:
- Special albums with plastic pockets where the coins are.
- Cardboard tablets with round coin slots.
- Glass cases. In such a pencil case you can not only store, but also view valuable coins without getting them out of there.
Frequent touching the coins exposes them to a bad effect, so you need to take them by the edge. If you still had to take them out of the field, then immediately you need to rinse with warm water and dry.
Observing all the rules for cleaning and storing copper coins, you can be sure: the most valuable copies of your collection will delight you with their appearance for a long time. Do not forget that copper is not too hard metal and must be handled with care.
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 are dark brown and sometimes black in 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.
Preparation for cleaning
Each metal has the property of being oxidized and coated with a green coating. Oxidation is sometimes confused with ordinary old stagnant mud. Therefore, first you need to check this option, try washing with ordinary water, you can use a toothbrush or a rag for this. If failed, then you need to clean the coin from green plaque and oxide in other ways.
At this stage, the main thing is to strictly follow the instructions, especially for old coins, which can be damaged much more easily. The cleaning method will depend on what kind of erosion we are dealing with.
Among other things, stock up on dishes, an unnecessary newspaper and a soft cloth. It will not be superfluous to have gloves ready to protect your hands.
General cleaning process
Before you start cleaning coins at home, you need to understand what we are dealing with and what exactly we will launder from. This type of oxide as copperfish is very harmful, because it releases toxic substances in contact with air, which means that it is constant. It’s very difficult to clean it.
Another kind of patina. In this case, the opposite is true, nothing needs to be done since it protects the metal. It is also called a noble plaque. Patina protects against the harmful effects of air and humidity.
Before cleaning from plaque, it is necessary to wash well from any dirt and earth. This is done so that the below methods are in contact with copper and not dirt on it.
A universal method since lemon is used to launder many materials. How to clean copper coins with lemon at home? You just need to take a coin and insert it into half the fruit. Leave there for half an hour and stretch. We rinse off all the excess, you can wipe off the remains with a toothbrush. Now, using a pre-prepared rag, wipe it dry. This method is probably the best and also very simple.
How to clear an old copper coin? For this we use the safest way. We will need baby soap. We rub it on a grater and fill in such an amount of water so that a mass resembling plasticine is formed. We immerse the product in the resulting mixture and leave it for a while. We periodically remove and see if pieces of plaque exfoliate, if so, clean and dip again. The procedure is performed until complete cleansing.
Often this is the cleaning of the most delicate tsarist and Soviet coins. Sometimes it may take days or even weeks until complete cleansing.
Salt, flour and vinegar
Take a tablespoon of flour and salt, add a drop of vinegar, mix. Rub the coin, leave for 10-15 minutes in this condition. We rinse off the residue under wastewater and wipe dry. It is better not to hold longer, as black spots may form.
For the vinegar method, we need a small dish in which we will heat the water. Pour a glass of water into it, add 2-3 tablespoons of vinegar and the same amount of salt. Copper coins will be cleaned there after immersion in hot water. We wait until everything cools down to ambient temperature. After that, a toothbrush is cleaned. Now wash and wipe dry.
You can buy them in workshops and jewelry stores, then clean copper coins at home. The process itself is very simple, just submerge in a liquid for 10-20 minutes and wipe dry.
Cola is not only a drink, but also a great cleanser. Easily corrodes plaque and even rust. It is better to use only as a means for digestion. She will handle cleaning a copper coin. To do this, immerse the item in the drink for several days, in difficult cases for the whole week. For faster results, put in the sun. When Coca-Cola is heated, its cleaning properties increase and the effect will be sooner. When the time is up, wash the coin and wipe it. Pour the drink.
We take our item and put it in a bowl of warm water. Add soda to it and leave for half an hour. Now with a brush you need to remove plaque. We rinse everything off with running water and dry it.
Antique coins in this way are best avoided. Use only in extreme cases, when the pollution is especially strong and other methods do not help. We will use caustic soda. Bred in cold water. It’s better to have gloves on your hands now. Using tweezers, lower the item into the prepared water and leave it for 5 minutes. We take out and rinse well under wastewater.
Attention. If blue or green spots form on the copper during cleaning, remove the coin and rinse. Otherwise, irreparable harm can be caused by this method.
The better to clean blacks and greens from a copper coin
How to remove greens from a copper coin? It's simple, we need ammonia, in it we need to moisten a cotton pad and wipe it. Now make a soap solution and rinse the item there, leave it in the solution for a few more minutes. We wipe again from greens and other spots and rinse in clean water. So you can quickly clean copper coins at home.
Put patina on the coin
To preserve a presentable copper coin, it is important to apply a patina that will protect against external influences.
- Light a fire (you can also gas, but preferably a fire) and pour water into a pot that is not a pity. Add to it 50 grams of copper sulfate and 5 potassium permanganate for each liter of water.
- When the water reaches a boil, extinguish the fire and put the coins in the pan, while stirring constantly. Watch the color of copper objects, it should change.
- When the color changes, take out the coins and lay them out to dry.
- We preserve the patina with a solution of benzene and alcohol in a ratio of 1: 1.
- Using vegetable oil, wipe.
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. For starters, it’s worth knowing 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 - in a few weeks it will change.
- 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 clean the collection in another, more secure way. Numismatists know very well how to clean copper coins with household soap. To do this, they 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 it (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 dip the coin in ethanol for a few minutes to remove the fat. После этой процедуры она может занять достойное место в вашей коллекции.
Как очистить медные монеты от окисления
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 look at 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 there is a lot of the mentioned metal in her alloy or that she 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.
Soap solution for coins (extract)
It allows you to clean the most persistent dirt on the surface of metallic money, but it has advantages and disadvantages. I must say that the method is the most sparing, allows not only to save features, but also to return the coin to its original form, if, of course, it was not damaged mechanically.
With a soapy solution, begin any cleaning at home. Soaking in a slurry made from soap is a more effective cleaning method. You will need:
- Laundry soap.
- Water 100-150 ml.
Grate the soap on a coarse grater, pour in water and mix the composition. After a while, when the soap swells, immerse the coins in the resulting slurry. If necessary, add water to the mixture, the consistency should be slightly thicker than sour cream.
After 2 days, remove them from the pulp, gently rub with a soft bristled toothbrush, and dip them again in the soap mixture. Please note that the prepared composition dries out over time, add water so that the mixture does not lose its consistency. The exposure time depends on the degree of contamination. Sometimes it takes up to 1.5 months, which is an obvious disadvantage of this method. But the result is excellent, and the money will not be damaged.
The method will help to tidy even the royal coins, the integrity of which is especially important to maintain.
Cleaning coins with soda (cooking)
The method allows you to clean copper money from stains, plaque and other contaminants. You will need:
- Baking soda 3-4 tbsp. spoons.
- Water 0.5 liters.
Mix the ingredients, immerse the coins in a container and set it on fire. The solution should cover the coins no more than 2-3 cm. Boil and cook the coins for about 30 minutes. Then brush them with a toothbrush using soda pulp.
Cleaning coins with ammonia
To clean coins from plaque, blackness or greens, ammonia will help. The method is simple and effective. It allows you to get the result in the first minutes of using the product. First, rinse the coin in a soapy solution, and then clean it with a cotton swab dipped in ammonia. Then you need to wash it again in soapy water.
The effect is achieved due to the action of ammonia, which combines with copper particles, which provoke the appearance of black or green plaque. This method is quite traumatic for copper coins, as it destroys their integrity on the surface. Particularly valuable specimens should not be abused and soaked in ammonia.
Cleaning copper nickel coins with vinegar
Cupronickel (copper - nickel) coins of the USSR are very difficult to clean. It is almost impossible to bring them to an impeccable and pristine appearance, and all numismatists and treasure hunters know about this. But this does not mean at all that purging money from a copper-nickel alloy is pointless. On the contrary, one should not let such values rot and deteriorate further, but one must be prepared for the fact that the result will not be long-term.
Take the following ingredients:
- Acetic essence 1 part.
- Water 10 parts.
Mix the components and immerse a coin in the resulting composition, the solution should completely cover it from above. You can soak several at once. Every 12 hours, they must be removed and brushed off with a toothbrush. From 3 to 10 such procedures are required, depending on the degree of oxidation. The cleaning is completed by drying - first it must be wiped with alcohol, and then put for several days in a warm place, and only then in an album with a collection of tsarist and Soviet-era coins.
Acetic salt method to clear coins
Coins of the USSR from a copper-nickel alloy can be cleaned with acetic-saline solution. This method consists of several stages:
- Take a small container, pour 100 ml of vinegar into it and add 1 tbsp. a spoonful of salt. Shuffle.
- Immerse the money previously washed with soap in the solution so that it is completely covered.
- Then you can see the chemical reaction - the surface will begin to turn white, and its contents will become more clearly visible.
- After 10-15 minutes, the coin can be removed with tweezers, and then clean it gently with an eraser. Repeat the whole procedure again if necessary.
In no case do not heat the vinegar-salt solution, otherwise the coins will be completely damaged.
After cleaning with vinegar, patina damage is possible, caverns and other uneven parts may open, you should be especially careful.
The mechanical method is the best and preferred for most numismatists. It is carried out using a special tool under a microscope. It is carried out by experienced restorers, since it is important not to harm, but to help the coins recover. If you own a valuable ancient coin, do not try to clean it yourself. Choose a method of mechanical cleaning, passing it to specialists.
Cleaning copper coins is a rather time-consuming process that requires concentration, respect for proportions in the preparation of solutions and aging periods. But as a result, you will save your finds and be able to replenish your collection with new items.
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, 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 a smooth and beautiful patina.
If you still poorly know in practice how to clean copper coins, 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, one 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, 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!