If you can see the fingerprint, acetone won't help. You would have to dip it if silver, live with it if copper or CuNi. Acetone works well before the fingerprint etches into the metal, but you can't really see it then, so you have to make a judgment.
Sandblaster, Grinder etc. If it hasn't etched the surface yet and you don't want to use acetone then iso-propanol (rubbing alcohol) find a bottle with the highest alcohol content you can. 91% is going to be about the highest you'll find. (It absorbs water and even water vapor out of the air so readily that anything over 95% is practically impossible.)
you just live with it if it's been there a while. I have an '09vdb in a pcgs64 holder with 1 plain print on the right of lincoln. i think it's cool. probably from the first guty to hold the coin back then.
