As echidna said WD40 will do the trick but rubbing with a soft cloth can be abrasive.My technique is to then apply a film of dishwahing liquid to the coin gently rubbing it in
BTW the film of dishwashing liquid prevents your fingers from actually touching the coin surface.Then rinse off with warm water and dab dry with a soft cloth.I've restored lots of coins this way which were then successfuly graded by PCGS of which many graded MS so it is a proven method given to me by an old collector many years ago
Edited by stevo1962
10/21/2020 11:42 pm