I soaked three pennies (1863, 1882, 1900) in acetone for about 10 minutes and then let them air dry prior to putting them in two X twos. In two of the three coins, what looks to be fresh wear on the front knee appeared. The two coins on which this happened were the least worn of the three (the 1863 and the 1900). Anyone else have this problem? Any suggestions for how to tell which coins may do this in the future?
my guess would be to look for the high points with a loupe/magnifyer of each coin before you soak them.
Doug is extremely doubtful about using acetone on copper and claims it causes some weird toning. Don't know if that is what you are seeing.
I suspect that spirityoda is on to the issue. The place where the fresh looking wear is on the high points. Those areas may be kept from toning with the rest of the coin because normal wear keeps setting it back. This not a color issue. The copper areas are on the same spot on both coins with the lesser worn coin being slightly more extensive. The color looks like any normal copper coin that has been in circulation so I do not think the acetone did anything more than remove crude that was hiding the worn areas. Thanks for the input.
