Green stuff on silver coin, what is it? 2 2

[Liverpool 4 ever]

This vintage Bulgarian silver coin has 835 silver content. it is in fairly good shape and would have eye appeal except for the green stuff on one side of the coin.  Not sure about to this greenish stuff and wonder whether this coin could be graded as it is or it needs conservation.  If, on the other hand, it is is a corrosion, then I would likely discard the coin. I  would appreciate hearing from you. Thank you    

[TPRC]

It will not grade like that. It is PVC.  You can take it off with an acetone soak probably, but there may be some permanent damage underneath it.

[Liverpool 4 ever]

TPRC, thank you very much. I followed you advise and placed it in a jar with acetone. Will post a shot of the coin after the acetone bath. Cheers 

[Mohawk]

TPRC is right.....it's PVC.  Acetone may help, but it's a mystery what's under the PVC.  Only one way to find out....soak it and see how bad it is under there.  Best of Luck!!

[Liverpool 4 ever]

On 9/19/2021 at 6:01 PM, Mohawk said:

TPRC is right.....it's PVC.  Acetone may help, but it's a mystery what's under the PVC.  Only one way to find out....soak it and see how bad it is under there.  Best of Luck!!

Thank you Mohawk.  I am learning a great deal from this board and from people like you and TPRC. 

Speaking about "problem" coins, I have another question this time regarding iron coins.  As you probably know, during the WWII Germany allies, Finland, Hungary and Bulgaria, plus few other occupied countries, such as Norway, minted iron coins as they run out of copper and other metals. Those iron coins were emergency coins and were not expected to last.  Nowadays, collecting pure iron coins in good conditions (as opposed to alloy covered iron coins) is somewhat challenging because of air exposure over time leading to coins oxidation.  I have few of those coins and I would be very thankful if you take a look at the attached photos and advise on possible coin conservations. Thank you   

[Mohawk]

Hi Liverpool 4 Ever!!

Well, I've only owned a few Iron coins in my time as a collector and yours look very nice for iron.  I've seen very few older iron coins with no rust on them whatsoever and the rust on your coins is very, very light.  What I would do is honestly leave them be....they're attractive as they are.  If you could find an Airtite type holder that they would fit in, I'd definitely do that as it would help them stay out of the air.  But I think they're nice just as they are  

[RWB]

On 9/19/2021 at 1:37 PM, Liverpool 4 ever said:

Not sure about to this greenish stuff and wonder whether this coin could be graded as it is or it needs conservation.  If, on the other hand, it is is a corrosion, then I would likely discard the coin. I  would appreciate hearing from you. Thank you  

The green stuff is one of several decomposition products of Di (2-ethylhexyl) phthalate (DOP) commonly used to make polyvinylchloride flexible. A trademarked product, Jayflex™ diisononyl phthalate (DINP) plasticizer, has replaced DOP in some applications. PVC without plasticizer is hard and brittle.

Edited September 20, 2021 by RWB

[Liverpool 4 ever]

On 9/19/2021 at 7:48 PM, RWB said:

The green stuff is one of several decomposition products of Di (2-ethylhexyl) phthalate (DOP) commonly used to make polyvinylchloride flexible. A trademarked product, Jayflex™ diisononyl phthalate (DINP) plasticizer, has replaced DOP is some applications. PVC without plasticizer is hard and brittle.

 

RWB, much appreciated!

[RWB]

Coin collectors commonly refer to the green slime as PVC contamination because 2x2 soft plastic coin flips are the most common source of contamination, and most of these are made with flexible PVC. You can purchase Mylar 2x2 flips which do not have plasticizes and are generally safe for coins. Iron and low carbon steel coins have their own problems due to moisture that can be present in any coin holder.

[Liverpool 4 ever]

RWB,  thank you again. Feel like I am at school asking questions and the answers come fast, furious and overwhelming. Here are the shots I just took of an iron coin which is a bit of rarity and needs some care. I have seen same coins with their original steely look, but they were worn down and I think they have been cleaned.  Aside from Mohawk's advise to keep them in airtite holders, would you recommend this coin for professional conservation with NGC?   Thanks 

[Liverpool 4 ever]

On 9/19/2021 at 7:31 PM, Mohawk said:

Hi Liverpool 4 Ever!!

Well, I've only owned a few Iron coins in my time as a collector and yours look very nice for iron.  I've seen very few older iron coins with no rust on them whatsoever and the rust on your coins is very, very light.  What I would do is honestly leave them be....they're attractive as they are.  If you could find an Airtite type holder that they would fit in, I'd definitely do that as it would help them stay out of the air.  But I think they're nice just as they are  

Thank you Mohawk.  Yes indeed, they are attractive as they are. Will move them to airtite round plastic holders 

[Mohawk]

Excellent.  They should do well in there.  And I'd be careful with any conservation with reactive metals like iron.  I've never seen what happens with iron, but I've seen a collector with some Polish zinc coins that didn't do so well with conservation.  They originally had some residue on them and the conservation got the residue off, but, man, were the coins ugly afterward!!! I'd hate to see something like that happen to your iron coins.  There are coins that conservation can help but there are also coins that conservation can annihilate. 

[Liverpool 4 ever]

On 9/19/2021 at 9:07 PM, Mohawk said:

Excellent.  They should do well in there.  And I'd be careful with any conservation with reactive metals like iron.  I've never seen what happens with iron, but I've seen a collector with some Polish zinc coins that didn't do so well with conservation.  They originally had some residue on them and the conservation got the residue off, but, man, were the coins ugly afterward!!! I'd hate to see something like that happen to your iron coins.  There are coins that conservation can help but there are also coins that conservation can annihilate. 

 

On 9/19/2021 at 9:07 PM, Mohawk said:

Excellent.  They should do well in there.  And I'd be careful with any conservation with reactive metals like iron.  I've never seen what happens with iron, but I've seen a collector with some Polish zinc coins that didn't do so well with conservation.  They originally had some residue on them and the conservation got the residue off, but, man, were the coins ugly afterward!!! I'd hate to see something like that happen to your iron coins.  There are coins that conservation can help but there are also coins that conservation can annihilate. 

Noted, Mohawk.  I myself have ruined some copper and silver coins and learned the lesson of staying away from coins experiments 

[VKurtB]

Zinc coins are among the toughest that exist to keep chemically stable.

[Henri Charriere]

[Whatever happened to the word "patina," or has it fallen out of favor?  And nary a mention of "verdigris" anymore.  Why?]

[VKurtB]

On 9/22/2021 at 9:09 AM, Quintus Arrius said:

[Whatever happened to the word "patina," or has it fallen out of favor?  And nary a mention of "verdigris" anymore.  Why?]

Because Andromeda Strain is what it is. It started out deadly, and if I recall correctly it killed many people and animals. Then they threw ivermectin and hydrochloroquine at it and it mutated to a benign state, infecting only coins stored with vinyl. Or something like that…

[RWB]

"Patina" was commonly applied to copper coins with natural oxidation. Then greedy sellers began calling anything "patina" and eventually killed use of a perfectly good word.

I recall "verdigris" still being applied to green/aqua colored corrosion on copper and brass coins - especially ancients. It is usually a mixture of sulfur and oxygen compounds with copper and low quality zinc.Sometimes called "bronze disease," I think.

Edited September 23, 2021 by RWB
correct spelling