Cleaning coins is almost always a bad idea. Why? Collectors are much more interested
in collecting coins in their natural state. Cleaning therefore almost always lowers
the value of a coin, sometimes as much as 90% of its original value. Remember: once
a coin is cleaned, you cannot unclean it. Also you should know light toning does not
affect the value of a gold coin.
If however you are still adamant about cleaning the coin, the best advice for you is:
"Take it to a professional to have it cleaned." Many professionals offer cleaning services.
The methods they use should not be attempted by most collectors. In cases of extreme
corrosion, they can advise you weather or not the coin (after it is cleaned) is worth
the cost of cleaning. A professional can also advise you on the best method of cleaning
if you decide to clean it yourself.
Selecting the method of cleaning that causes the least damage to a coin is the
obvious choice. Once you decide upon a method of cleaning your coin, use another
less valuable coin for experimentation.
One final point that should be made before you decide whether or not to clean your
coin is this: When selling a coin that has been cleaned, you should always advise
prospective buyers of the fact that it has been cleaned.
The Knave of Coins