Expert: PAPAJACK - 4/25/2008

Question
I am a begining Lincoln cent collector. Is there any accepted and non-devaluing way to clean coins? Some of the older cents are quite grubby. I asked this question of Neal and he sent me a response that he answered this question for me once before, although, it was the FIRST time I ever contacted him.

Answer
Hello Doyle,                          

Let me state as a Coin Collector that coins are worth much less to coin collectors after having been cleaned. There is usually no reason to clean a coin. Unless the substance on the coin is destroying the coin (like acid, PVC damage etc.) it is not necessary to clean it. Any coin that has ever been cleaned will sell for less.
True coin collectors don't recommend cleaning coins at all.
When a coin is cleaned the original surface is removed thus removing the luster that the purest collectors want to see.
The cleaned surface allows other contaminates to attack the surface. Also the cleaning may deposit other particles on the surface.
Also note that coins that are naturally toned (especially silver coins) bring higher prices than cleaned coins. Usually double the amount. Also if the coins have an unusual blue, olive, or rainbow colored toning they sometimes can be sold for many times their usual price.

Now just from experience;
This is a good question though and other than a liquid detergent and distilled water cleaning and pat dry I haven’t heard of a restorative process that is cost effective.

You can try other PH natural inert solvents at your own risk like lacquer thinner, acetone etc…

I have not tried it but some people have said letting it soak in non corrosive oil (olive oil, gun oil etc.) wiping and washing or even chipping away at crusty dirt with a tooth pick or orange stick.

Solutions that are too acid or basic will change the surface of the coin since copper is very reactive.

I notice on some older large cent copper coins that there is a shellac or lacquer coating on them. Possibly done to preserve the finish but more likely to hide defects. I have never tried to remove it.

Only expensive coins I would send to a conservator like NCS:
http://www.ncscoin.com/

Thank You and Good Luck

PapaJack