A question I get quite often from my customers is “what can I use to clean my coins?” The short answer is don’t clean your coins under any
circumstance! The reason being that no matter what is used to clean a coin, a certain amount of damage will occur to that coin. Also, a cleaned coin looks different from natural coins and cleaning can be detected by collectors. Coins take on a certain appearance due to their age and circulation. Collectors want coins that look natural and in many cases won’t add cleaned coins to their collection.

Coins that are minted in copper or silver are most likely to turn dark or as we say “tone” when left exposed to the air. The way to avoid that happening is to store coins in an air tight holder so air won’t come in contact with the surface of the coin. This is especially important when storing uncirculated or high grade coins that still have the mint luster. There are many products available that will protect them from the air, but no matter what you use, always keep a close watch on your coins to make sure nothing is happening to them. If any change whatsoever occurs in their appearance, change the container they are in.

Improper cleaning results in the loss of a small amount of metal from the surface of the coin. Repeated cleaning can actually lower the grade of a coin by removing too much metal. Some recent examples I’ve seen in my store include a woman who brought in a silver dollar. During one of my interviews on the radio I had mentioned that any silver dollar with a “CC” mintmark (which stands for Carson City) is more valuable than others. This woman found one in her collection and brought it in for me to evaluate. Unfortunately, the coin looked a little dark to her, so to brighten it up she used an eraser to remove the oxidation. The result was the coin had hundreds of scratches in its surface from the eraser which ruined its collector value. If it had not been cleaned it would have been worth over $100, but now it is worth less than $50.

Another example that occurred many years ago, a gentleman called to say he had an original roll of 1847 half dollars in uncirculated condition and inquired as to their value. At that time the coins were worth around $200 each, making the roll worth about $4000. When he brought the coins to me, it was obvious they had been cleaned many times, which he admitted to doing. He said that every time he cleaned them they would only get dark again, making him clean them again. Unfortunately he reduced the value from $200 each to about $20 each.

There is a professional service that can clean coins without causing harm. Some of the work they do involves cleaning coins that have been recovered from shipwrecks and coins that have been in a fire. But this is limited to coins that have substantial collector value as the service comes with a price.