I have had most of my coin collection sitting on the table while I waited for flips to arrive. Well in the 2-3 weeks they have been out, about 25% of my coins have developed green splotches on them. Doesn't matter if they were copper, silver, or nickel. My temp stays at 67 degrees 24/7. The humidity is controlled and kept very low. I have not sneezed, coughed, etc near them, nor sprayed anything like glass cleaner near them. I can't understand how this happened. I am really depressed because a few coins that were ruined were some high grade examples I had.
no, it would leave a fingerprint which would embed itself. I hold all my coins by the edge, just touched that one because it's already ruined.
did you clean the table first. its never a good ideal just the leave them open in air 2-3 weeks deadskin would defiantly gather
That sucks. Didn't know such things can make coins discolor. I thought pvc or humidity only does that.
I would bet the spots were already there and you did not see them. They may have became worse from being out in the open.
I agree with spirityoda, definitely looks like PVC damage. Were the coins stored in something inert prior to you leaving them out? NCS can help with PVC issues, so long as you catch it before the damage to the coin is irreversable. The coin that you are holding looks salvageable -- for a cost.
About a year ago I bought a holdered Civil War token (MS-63) that turned green. It was the same stuff.
Possibly... the spot is verdigris. As such, touching the coins could introduce moisture onto the coin surface.
