Green Haze on Old Silver

Okay, my grandparents had some old silver coins stashed away. Most of them have been left loose in old coin purses that look to have a leather or fake leather lining. There are also quite a few that have been thrown in together in a big paper envelope. I would venture to guess that they've been stored in this way for the better part of the past 40 or 50 years at least! A large majority of the coins have what appears to be a light green haze over them, particularly on the edges of the coins. It's not big, bold spots of green (in most cases), but just a hazy film over the edges of the coins. Mind you, these are mostly 90% silver coins with some 40%'s thrown in too, not copper. So, what could this be? Do you think it might be verdigris of some sort? And, what should I do about it? I want to remove it from the coins. What do you think I should try? For the most part, these are what most would term "junk" silver coins, so no big rarities here. For the couple of rarer coins that have issues, I'm thinking of sending those to NCS anyway. I tried to take pictures of the haze, but it doesn't show up in the pictures. Also, in some lighting conditions, it can hardly be seen. In others, it's much more noticeable.

Any ideas? Thanks!

 

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tcore:
It seems strange that the coins were stored this way, and what you are describing seems to be PVC. That is the gunk that you get from old soft plastic coin holders.
The PVC is what keeps the plastic soft, but it degrades and forms that green gunk.
Anyway, I would try actetone, on a few of the 'junk silver' pieces.
Just use carefully, and rinse the conis thoroughly, then air gry, be sure there are no water spots they may stain coins.
Also, be careful not to rub the coins.
Good Luck.
The Other Frank

 

That is characteristic of PVC from storage in soft plastic flips or bags.

Do a forum search on "PVC acetone" and you will find extensive discussions of the best method to remove that gunk safely.

 

Yeah, that's just strange though. I'm positive they've been in these coin purses for the past 40 or 50 years. As far as that being a strange way to store coins as TreasHunt said, you have to understand, my great-grandparents are the ones that put the coins away and they weren't putting the coins away as collectibles. They were putting them away to stash away some silver for hard times, so I don't think keeping them in coin purses is that abnormal. I wonder if the coin purses are some kind of fake plasticized leather that contains PVC. I might have to try acetone on a few of the coins just to see what we can do. Thanks for the input. Any other input is also welcome.

 

Tcore:
"As far as that being a strange way to store coins as TreasHunt said, you have to understand, my great-grandparents are the ones that put the coins away and they weren't putting the coins away as collectibles. They were putting them away to stash away some silver for hard times, so I don't think keeping them in coin purses is that abnormal."

I was referring to the apparent PVC, not the use of the purses, it is strange to have developed PVC residue from leather purses, normally, I have seen that the leather turns the silver black, or at least dark.
The Other Frank

 

I'm not too sure if plastics were common 50 years ago. If you said 30, I can understand but 50? Maybe it's some other type of "toning" you got there.

 

I think gxseries might be correct- "fake leather" could indeed be vinyl, as in poly(vinyl chloride), i.e. PVC...

 

FWIW Polyvinyl-Chloride IS the plastic.

 

AH vinyl can possibly be the reason. It got popular around 1930ish so that can be a possiblity. Never thought of it.

 

Yeahhhhhhh...... Got a little bit of that issue too. They've got a few Bust Halves that were stored in a leather wallet that toned them darn near black.

What's the general concensus on what to do with coins that are toned black or very dark? I know I've seen GD mention before that if toning gets to that point, it's damaging the coin.

 

The PVC from pleather (fake vinyl leather stuff) or whatever the kids are calling it nowadays had crossed my mind. But, yes, I really wondered if it could be some kind of toning other than that.

 

Fake leather is what is called PVC- polyvinyl chloride (with some softening agents included- these cause the typical smell you get from transparent vinyl sheets and can sometimes help you tell that you have PVC involved in the situation). The 90% silver coins, DO contain 10% copper (I guess you are talking about the 1932-64 Quarters), and this copper leaches some of the chlorine to form CupricChloride (which happens to be green). This is especially the case if the material was kept in warm conditions. Any whitish/grey/black residue formed would be Silver Chloride.
The sad part is, since the coin material itself is part of the haze, the coin surface has already been damaged, even though the haze is not too terribly difficult to get off.

 

After many years, Leather Purses and Coin Albums usually always develop a green mold in or on them! This is partially due to the material being Leather but due more to the chemicals used to tan the leather which mainly consists of salts. The salt attracts moisture to the leather and the combination of the salt, leather and many years, produces a green mold. That is why, it is never a good idea to store coins in Leather Purses or Leather Coin Albums.

Sometimes, Alcohol or Acetone will remove some or all of the green mold from the coin. However, if the coins are pitted from the salts, then too much damage has been done and the value of the coins has been seriously compromised.


The Other, Other Frank

 

Good ideas. Thanks!

 

This is the answer that is probably the most likely true. PVC was not extensively used for purses. However, back in the early days of plastics a substance was used called ABS which is now outlawed. I like the leather tanning salts the best. If Acetone will not remove that green haze, leave it alone.

 

And all these years my wife has been telling me it was age spots!!!

 

Ha ha ha... I think I'll leave cleaning those spots off to your wife.

 

Did she try dipping you in acetone?

 

LMAO. Nice learning thread ending ina hoot. I love it. Thanks


Tom