Other than just soap and water.It is not good to clean a coin to most coin collectors.To some it does not matter.You would gain more turst if you did more verifications thru Listia.
Araiderfan you are wrong.I spoke to many professional coin collectors and all agree that if you use just soap and water to clean a coin this is fine.Common sence is needed with everything including this area.A light rubbing with plastic or rubber gloves by itself is good to get any surface dirt,dust or sticky stuff off.None of the details of the coin will be touched.No one wants a coin in this condition.Patina is tarnish or toning of the surface that happens with age.This does not devalue a coin.Sometimes even makes it more valuable.I sell coins for melt value so I get a flat rate of the silver or gold at spot price.Some people sell and buy coins at different places for different prices.