So if I have a coin that I want to clean up to see the details, I use a dremel tool with either a wire-wheel bit or a nylon brush bit. Yeah I know you aren't "supposed" to clean coins....but if it is a NON key-date coin like a 1908 V NICK, who cares!?!? I'd rather be able to see my coin than look at a crusty red hunk. That's just my opinion! However, if it's like the 1921-D Mercury dime I found: DONT DO A THING!!! Maybe a water rinse and that's it! Put inside a case and leave it begood luck!