Ok, a lot of talk around here by newer people (such as myself) has been about PVC damage? I read someone describe it as a "green gunk" and I have a coin with green gunk on it. A long time ago I bought a really ugly 1921-S Morgan Dollar to fill a gap in my Dansco Book (I never bought a nice set of 1921s-all mine are junk). Anyway, on the back is has "green gunk" on it and I'm wondering if this is PVC damage...or like glue or something? Also (I'm almost imbarrased to post pics of this coin) but it has an ugly black mark on the obverse. I have always assumed its some sort of chemical stain (Paint?) but I really have no idea. Anyway got a thought? Anyway, I was just curious. I really don't care about trying to remove the green stuff (if it is PVC) with acetone or whatnot. It's just a 1921-S worth probably $7 anyway. I was just asking more for my own personal reference. Thanks!!! :hail:
I think that's something other than PVC, too. Possibly glue or paint. PVC residue is usually a thin, greenish, gummy substance. "PVC damadge" is what happens to a coin's surface after prolonged exposure to PVC. Uncirculated coins can lose their luster, and given enough time, the chemical can eat into the metal. The black circle, on the obverse looks like tarnish. It may have been in contact with something (like rubber?) that had a high sulfer content. Tough to tell.
The silver value of your coin is about $9.60. So you might make out okay with the coin in the long run even though it doesn't have much in the way of numismatic value. This is the type of coin you can have a little fun experimenting to clean it up without fear of damaging the value. I would at least try to remove the gunk with a toothpick.
I agree that the coin in question is not of such a value that a little experimenting would be fun and educational. First try the Acetone soaking for a little while and longer if no results. You may also want to try a solution of baking soda and distilled water. Always wash the coin with distilled water when finished with such experiments and blow dry or blot with a cottom ball. As to the type of contamination this coin has incurred, it is difficult to know exactly what it may be. However, since it appears to be primarily on one side, it may well be a heavy oxidation due to a partial exposure to the air being in some type of container. However, a greenish type of contamination dose not usually indicate Oxidation so several methods of removal may be required. One thing you may want to try is Laquer Thinner remembering your about to not help the value of this coin.
