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 Replies: 7 / Views: 3,857 |
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Valued Member
United States
258 Posts |
I recently removed some coins from clear, flexible plastic holders that had three pockets each about the size of a 2x2. They had been given as a gift years ago and contained several common coins with sentimental value. I took them out because I noticed several coins had small green spots on them, especially on an Ike, presumably PVC. They've been together in a coin purse for a couple months, so I was wondering if it would be alright to place them in tubes with other "untainted" coins, or is there a danger of those spots (presumbably PVC) spreading to the other coins?  |
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Bedrock of the Community
United States
19935 Posts |
Contaminated/corroded coins should ALWAYS be kept away from non-corroded coins because they will supply feed materials.
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Moderator
 United States
23522 Posts |
This is a process which does not stop once started, so the ones you already see green on will be destroyed if you do not intervene. Yes, they can "infect" other adjacent coins as well.
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Pillar of the Community
 United States
5828 Posts |
It's like a virus. Ever wonder why a TPG wont accept any coin with visble PVC damage (well, that's what I've heard)? |
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Bedrock of the Community
United States
20753 Posts |
Difficult to explain but almost any contaminates on coins or any metals can go from one to more of the same or even different materials. Usually only if touching though. Sort of like most viruses on people. Safe if kept apart. A method of testing this is to take a Copper wire that has been outside and is turning green. Wrap a new piece of clean Copper wire around that one and you'll see that one too starts to turn.
And too, pending the environment, such things happen faster during hot, warm, high humidity areas.
Another problem develops when dissimilar metals touch each other. They creates a small, but dangerous to the metals, electrical charge. It is the principal of some types of temperature detection known as thermocouples.
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Moderator
Australia
16809 Posts |
PVC is less "contagious" than "bronze disease". Bronze disease is dry and crumbly, and can spread from small bits of powdered corrosion breaking off one coin, drifting through the air or falling by gravity and landing on others. The damage caused by PVC goo is limited to what the goo actually touches, so coins have to be in direct contact with the goo to be affected by it.
If a PVC-affected coin feels "sticky" or "plasticky" compared to a normal coin, then it's got enough PVC goo on it to be a problem.
PVC goo is easy to remove; any organic solvent should do the trick. Acetone is the usual solvent recommended for the purpose, but methylated spirits, distilled alcohol (such as vodka) or petrol/gasoline should all also work well enough for the purpose, in a pinch.
We always recommend removing PVC goo when detected, because it's:
(a) ugly;
(b) un-natural, in the sense of "not acquired by the coin in it's natural use as a piece of circulating currency";
(c) easy to remove without damaging the rest of the coin; and
(d) continuing to damage the coin while it stays there.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Bedrock of the Community
Australia
21786 Posts |
I agree with Sap. The 'goo' is organic plasticizer that has leeched out of the soft PVC, to be deposited on the coins. It can be removed with acetone or other strong organic solvent.
Use a loupe to look closely for surface damage on each coin after it has been thoroughly cleaned.
If there is no evidence of any damage, it should be OK to store them in tubes, on top of each other.
If there is any evidence of surface corrosion left behind, I think that those coins should be stored separately.
Any of your more valuable coins should have individual protection anyway, even if it is only in a mylar / cardboard flip in a non PVC album page. The exception to this being bullion value only coins.
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Bedrock of the Community
United States
17884 Posts |
Quote:Ever wonder why a TPG wont accept any coin with visble PVC damage They will accept PVC DAMAGE (coin etched by PVC residue but the residue removed), but they will not accept coins with active PVC contamination (PVC residue still on the coin.). |
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Replies: 7 / Views: 3,857 |
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Posted 05/10/2015 1:36 pm
