That damage is irreversible. It may get lighter with acetone but it's already pitted. Nickel isn't supposed to rust like that so something went wrong. May have been a bad batch of nickel, or a really strong chemical. Looks to happen in any year of the Geo.V nickels. I've had a 1925 and 35 with the same type of ugliness

.
Edited by TerryT
04/17/2019 01:19 am