I have a coin (1883 nickel with cents) that has been in my collection for about ten years now. It's resided inside an Airtite capsule that entire time and stored in the same manner as all my other coins. Just last week I looked at it and to my horror it has started to gather some green pvc gunk along it's perimiters. Now, I guess my question is this....can pvc damage or contamination occur that long ago (before ten years when I aquired it) and not show any apparent signs until now, or is this a result of recent contact? If so, I can't for the life of me figure out how it came in contact with pvc materials while no other coins in my collection were effected. This has been baffling me all week! Guy~
whoa, I've never heard of this happening to coins in the airtites... will be interested in what others have to say stainless
First, are you sure it is PVC rather than nickle corrosion like verdigris on copper coins. Nickle can make similar colored compounds ( some of my artist's oils use nickle compounds for a bluish green color. You can tell by putting the coin in pure acetone. PVC "gunk" will dissolve, the corrosion will not. I put every coin I obtain through an acetone bath before I put it into a permanent holder. Unfortunately , I only started this after several of my earlier obtained coins developed finderprints after 10-20 years.If I had done this, some of my Lincoln proofs would be pristine Air-Tites are not air tight! They are not much or any more airtight than a coin in a tightly stapled mylar lined 2X2. They are nice holders, they physically protect the coin well, but 10 years is plenty of time for environmental corrosion to start. Often Ait-Tites users get overconfident as do slab owners about the safety from the environment. I am hoping it is something easily dissolved in acetone. Good Luck. Jim
Thanks Jim. Fortunately it was removed with acetone. I just can't figure out how it became contaminated, unless it had been all that time and the color just now showed. I've never had such problems with any of my other coins, so I was a bit concerned. How long would it take pvc damage to show up on a coin from the time it was infected? Is it even possible it could have sat that long with no visible signs until recently? Guy~
It could have been so small a focal area that it wasn't noticed and then as moisture and air entered the holder over the 10 years, the spot could have absorbed the moisture and increased its size. The way I understand the process ( and I will stand corrected if someone else has more authoratative info) is that plasticizers come out of the pvc flip or holder ( some plastic album sleeves had it also 20 yrs ago) and attach to the surface of the coin. On proofs which have smaller metal flow lines than business, the first sign is usually a haze which can damage the mirror like surface of proofs. On the coarser flow lined business strike, it can form thicker deposits and poduces the green gunk after it has absorbed enough moisture to react with the metal, the green actually shows the metal is being affected. Even taking it off with acetone can leave pits visible to TPG and sharp collectors if it has been active long enough. The best thing is for collectors to take the time to look carefully at their collection every few years for problems. I didn't, and learned a lesson. Very happy it came off, and I doubt there was much if any visible damage. Jim
Guy - let's back up a step here. First of all where exactly did you have the stored and what else was in the same space or container ?
Doug, I had it stored in my safe along with all my other coins. It's been in an Airtite, which in turn was inside a wood box, inside a large plastic storage container. The plastic container is pvc free...I made sure to find one that specifically said so, which seems to be most containers made to store foods. Nothing else is in the safe except for some important documents. I don't see where it could have come in contact with anything containing pvc unless it was contaminated before I bought it. But, this is a new experience for me, so any suggestions and help is more than welcome. Guy~
Do you have any old flips in the safe, plastic binders or sheets that go in the binders, how about the safe itself - what are the shelves made of and what is the safe lined with ? My point is that coins do not have to come into direct contact with the PVC material, they just have to be in the same space so that when the plastic starts breaking down the gas can come into contact with them. It can be something so simple and obvious that you would never think of it - until it's too late.
That may be it. I had a lot of old flips that may have contained pvc that I had kept in the safe in an envelope. They've been out for a while now, but had been in there several years. The safe itself has no lining, and the shelves are wood. Those old flips now reside outside the safe and are probably headed for the trash. Guy~
Wooden shelves are no good either, they put of acidic gas that can harm the coins. Get some metal or inert plastic shelves and get rid of the wood.
pvc................................... http://coins.about.com/od/caringforcoins/ht/pvc_damage.htm?nl=1 worth a read.
