My aunt invested in some coins and currency about 20 years ago. She wants me to sell it for her. I have a couple of dealers/friends who are appraising for me. The currency is fantastic and I'm going to buy it. Most of the coins are silver (Walkers, commems, standing liberty halves, barber halves) and have obvious PVC damage. (all the coins have been in PVC containing flips for at least 20 years - coins were stored in a safe deposit box.) Obviously, this significantly reduces their numismatic value. They all look washed out and green. However, my question is about a very nice 1914 s St. Gauden's double eagle included in the collection. Does PVC damage gold, too? This coin looks very nice except for a few minor copper spots. My dealer friends agree that it unlikely to be a counterfeit. I'm considering buying it for myself, but I'm worried about PVC problems. I'm worried about it being counterfeit, too. Many experts have been fooled by good fakes....and I'm certainly no expert. Also it is my understanding that PVC damage will eventually eat into the surface of the coin, destroying luster, causing pitting, etc. All coins are common dates and graded MS 63-64. Is it worth having them cleaned to see how extensive the damage is, or should I just sell them at a discount to a dealer willing to take a chance? Thanks a lot for your help.
I'll leave the definitive answer to others, but here's my understanding. The short answer is "Yes". Why? Because an older US gold coin is 90% gold and 10% copper. To the best of my knowledge PVC won't react with the gold but the copper is fair game.
That answer works for me. Only thing I would suggest is that the PVC be removed and then the coins be checked. You might be surprised and find some of them undamaged.
While the "PVC" residue may affect the gold coins due to their copper content, I would expect the main result of that to be making the copper spots more noticeable. As a rule the very high gold content is good enough to protect the copper for acid attack, so the only places it would really occur would be on those areas of unusually high copper concentration ie: the copper spots.
