Coin and Paper Money Collecting/Should I clean my coins?


Hello David,
I am 53 years old and have been an amateur coin collector my whole life. I am now very interested in metal detecting and I am finding some older coins. Most older coins I find metal detecting are usually not in the best condition due several reasons. My question is should I attempt to clean these coins? and if so any suggestions how?
Thank you, Randy

Hello Randy,

Thank you so much for your question.

I was a collector for almost 30 years before I opened my store; I was also an avid metal detector/digger. Just 5 months ago we became a dealer for White's Metal Detectors and we have met dozens of people like you and they all have the same question.

In short you should never ever under any circumstances clean a coin. Restoring any potentially valuable collectible without the proper knowledge, tools and skills almost always ends badly. Remember back to your coin collecting days and how you would pass on obviously cleaned coins or coins that were scratched and otherwise damaged.

Some people do not care about the numismatic value, they only want to know if they have gold or silver and how much they can get for it. Many of the diggers that we work with have done far more damage to their finds, in fact the value lost often exceeds the value that remains.

If you must clean your finds there are some very light cleaning techniques that will likely reduce the value but they will allow you to better understand what you found.

One of the least destructive things you can do is put your metallic finds in a bath of hot soapy water. I like to use Dawn dish washing liquid as it is very mild but will break the bonds of the dirt to the metal.

You should never handle the coins while they are soaking and only rinse them through a plastic or silicon strainer. Lay them on a towel to dry - don't pat or touch them, they will dry on their own. This should remove most of the surface dirt from your finds.

If you have copper coins that you simply can not identify due to encrusted dirt you can try soaking them in extra virgin olive oil. The oil will act like a natural cleaner, breaking the bonds with the dirt and other crusted materials. This can work fast - maybe over a few days or it can take years. There is no way of knowing ahead of time.

If you are sure that you have found only modern pocket change you can go ahead and place them in a mesh bag and throw them in your dishwasher or your washing machine. They will get nice and clean so you can spend them without getting dirty looks.

NGC and PCGS both offer restoration services if you have identified a rare but dirty coin. Pay them and let them do the work for you. They will do the best job and certify the coin when they are done.

Thanks again for your question and good luck with your metal detector.  

Coin and Paper Money Collecting

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David McConaghy


I can answer most questions about coin identification, grading and counterfeit detection. I can answer questions about US and Foreign coins & currency, ancient coins too.


30 years experience as a collector and dealer in rare coins ANA Numismatic Scholar Owner of New England Coin Exchange I have been buying and selling coins in RI for over 30 years

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