Over the years, dust, germs and other dirt accumulate on the coins, depriving them of their original luster and making them less beautiful. For this reason, it is recommended to clean them to bring them back to their initial conditions. However, remember that if you have collector coins, proofs, others that have never been in circulation or of great value, the cleaning process could affect their quality, damaging them to the point of reducing their value to that of the material they are made of.
Steps
Method 1 of 3: Wash the Coins
Step 1. Hold the coins under hot water
This way, you can get rid of the first layer of dirt thanks to the pressure with which the water comes out of the tap. The flow emitted by a normal home faucet is strong enough for this job, so avoid increasing the pressure with a sprayer, for example. You simply have to hold the coins under running water for a minute or two. When you're done, place them on a rag or paper towel.
- All coins can be washed with water; however, copper coins react to a greater quantity of substances than nickel or silver coins and consequently tend to be damaged more. In this case, it is difficult to get a good result with just water.
- Remember to close the drain with the stopper before washing the coins in the sink, to avoid losing them if they slip from your hands.
- Handle each coin separately, so that the water can hit them directly.
Step 2. Transfer them to a solution of dish soap and water
Create a cleaning mixture in a basin by mixing tap water and dish soap. Dip each coin individually, holding it between thumb and forefinger to scrub dirt off the surface. You should notice the debris peeling off the metal.
- If a coin is particularly dirty, you can soak it in soapy water.
- Non-abrasive solvents such as distilled water and a mild soap have sufficient cleaning power to wash your coins and do not contain acids that could corrode them.
Step 3. Brush them with an old soft-bristled toothbrush or scrub them with paper towels
Do this while the coins are still in the soapy water. Continue until the metal shines again. Rinse them often to prevent residues from visually scratching the surface. This procedure could cause fine scratches on ancient or precious coins, reducing their value.
- When finished, remember to do a final rinse.
- Don't rub them too hard; focus on one small area at a time and press gently.
Step 4. Dry the coins with a cloth
Take care of each one individually and store them in a dry place. Make sure there are no traces of moisture left before putting them away to prevent the metal from corroding over time. The coins should now be bright and shiny.
- Using a lint-free cloth will leave no residue on the coins.
- By blotting them, you avoid creating micro-scratches caused by the cloth you rub.
Method 2 of 3: Soak the Coins
Step 1. Make a solution of isopropyl alcohol and salt
These chemicals are abrasive, acidic and can clean the coin of any accumulated dirt. To make a "bath", mix 250 ml of isopropyl alcohol with two tablespoons of table salt in a bowl. Mix the ingredients and add the coins. Leave them to soak for anywhere between two hours and a week, depending on how dirty they are.
- Isopropyl alcohol is a universal solvent capable of dissolving non-water-soluble substances such as non-polar compounds.
- This substance has a strong odor and is flammable. Remember to open the windows when cleaning the coins with this method.
Step 2. Rinse the coins on the sink using distilled water
Tap water contains chemical additives, such as chlorine, which can corrode metal over time. By using that distillate you are sure to get rid of any chemical residue.
- Distilled water was filtered of all contaminants.
- You can buy it at the supermarket.
Step 3. Blot the coins with a cloth and let them dry
Turn them over and repeat the process. Do not stack them on top of each other immediately after the drying process, to make sure there are no traces of moisture that, over time, could cause damage.
- Extreme temperatures can alter the patina of the coins. Avoid drying them with a stream of hot air.
- If there is any residue of cotton or dust on the metal left by the cloth, blow it off but do not use can compressed air.
Step 4. Store the coins in acid-free plastic binders at room temperature
Other common materials, such as paper, cardboard, and some types of plastics, can ruin metal over time. Do not store them in polyvinyl chloride binders, or PVC, as they contain substances that damage the coins. Remember that environments that are too hot or too cold contribute to the degradation of the metal; make sure the coins are at room temperature and low in humidity.
- Do not store them in places where they can fall off, such as an unstable, high shelf.
- If you want to put them in a display, use a container with two pockets, made of polyethylene terephthalate, a polyester created specifically for storing coins.
Method 3 of 3: Clean Collector Coins
Step 1. Go to a professional
Before cleaning collector coins, you should always consult a specialist in numismatics. In fact, cleaning could enormously reduce the value of the coins; at times the alterations of the color and the patina caused by the exposure to the air affect the preciousness of the object. For this reason, you should never clean old or valuable coins.
- When handling ancient coins, always keep them by the edge. Oil and fingerprints could compromise its value.
- There is a standardized system for evaluating coins, so even the slightest scratch caused by cleaning can therefore create problems.
Step 2. Apply a thin layer of petroleum jelly using a cotton swab
Take a lint-free cloth and pat the coin to remove all the petroleum jelly. This way, you should also lift all unwanted dust and grime, without affecting the value of the coin. When doing this, be very cautious and use a magnifying glass.
- To apply petroleum jelly, you can use a cotton swab or a very soft synthetic brush.
- Don't overdo the product. Your goal is to apply the thinnest layer possible.
Step 3. Put the coins in an acetone bath for 5 seconds
If you leave residues of this solvent on the metal, a brownish patina forms which significantly reduces the value. It is very important to rinse immediately with distilled water, to remove all residual acetone before leaving them to air dry. Do not rub or rub ancient coins. Since acetone is a solvent and not an acid, it does not alter the preciousness of the coins unless you leave them exposed for too long.
- This substance is flammable; wear powder-free latex gloves if you decide to use it.
- If you are using a jar with distilled water, put a napkin on the bottom; the coins will not scratch on contact.
- Use 100% pure acetone. The other products contain chemicals that reset the value of the coins.
Step 4. Store the collectible coins in 5x5cm hard plastic bags
You can transfer the envelopes to a binder to have all the coins well exposed. Hard plastic is better because it is more durable and offers more protection. The most important thing you need to do is to make sure the bags are airtight and that the metal is not exposed to the surrounding environment.
- Get rid of any plastic that contains PVC. Buy coin pouches made from polyethylene terephthalate, as PVC damages metal over time.
- Protect ancient coins from paper clips and other metals.
- Do not use paper, as it contains sulfur and causes the coins to blacken.
Advice
- Keep the coins by the edge. If you grab both sides, the oil on your fingers will damage them over time.
- Handle the coins on a soft cloth to prevent damage if they fall.
