CGS and Verd...Sorry!

[Coinery 1,156]

I've just received my CGS 1922 3d, which I'm pleased with but, being as it's going into my wallet, it had to come out of the shell!

Shock-horror...where the edge was in contact with the 'ring' a lovely bright green problem was just developing, making me glad I took it out when I did!

Can I trust a slab from now on? Unless my intention is to sell it on and take advantage of its inflated value, then NO!

[pies 33]

What you using to clean, acetone?

PS you can spend it any more

[Coinery 1,156]

What you using to clean, acetone?

PS you can spend it any more

Yes, Acetone...love the stuff! I do have to tell the chemist what I'm planning to do with the stuff when I buy 2 bottles or more!

[Accumulator 52]

It can't be verd, as it's a silver coin. Most likely a deposit from an old PVC coin envelope. I'm not sure it's the responsibility of CGS to clean coins (other than a light dusting) before stabbing so it's really down to the previous owner.

[Coinery 1,156]

It can't be verd, as it's a silver coin. Most likely a deposit from an old PVC coin envelope. I'm not sure it's the responsibility of CGS to clean coins (other than a light dusting) before stabbing so it's really down to the previous owner.

.500 silver. The other 50% is vulnerable isn't it?

Edited February 28, 2013 by Coinery

[TomGoodheart 403]

It can't be verd, as it's a silver coin. Most likely a deposit from an old PVC coin envelope. I'm not sure it's the responsibility of CGS to clean coins (other than a light dusting) before stabbing so it's really down to the previous owner.

You do sometimes get green on hammered silver. I presume it's because the silver is mixed with copper to the correct fineness and sometimes you get a bit that's not so well mixed in and that's where the copper salts develop...

[Paulus 1,975]

It can't be verd, as it's a silver coin. Most likely a deposit from an old PVC coin envelope. I'm not sure it's the responsibility of CGS to clean coins (other than a light dusting) before stabbing so it's really down to the previous owner.

.500 silver. The other 50% is vulnerable isn't it?

I was just going to ask about that, how do you get verd on a silver coin, if it's not, but a deposit, is it corrosive, and could it have been caused by living in the slab??

Not surprised at your shock though Stuart!

[Accumulator 52]

I guess that's possible on an old hammered coin but it seems most unlikely in this case. The green/blue smudge looks more like reaction with a sweating PVC envelope. If it wipes off with acetone, it surely must be that, or just dirt?

[Peckris 579]

It can't be verd, as it's a silver coin. Most likely a deposit from an old PVC coin envelope. I'm not sure it's the responsibility of CGS to clean coins (other than a light dusting) before stabbing so it's really down to the previous owner.

.500 silver. The other 50% is vulnerable isn't it?

I was just going to ask about that, how do you get verd on a silver coin, if it's not, but a deposit, is it corrosive, and could it have been caused by living in the slab??

Not surprised at your shock though Stuart!

Yes, the non-silver 50% is mostly copper, so verdigris is possible.

Still getting over the shock that a humble 1922 3d would be slabbed!

[TomGoodheart 403]

Well, when I searched for "what is pvc green on coins?" several entries claimed that eventually pvc residue will damage a coin.

Not knowing much about the chemistry of the whole process of 'pvc sweating' I don't know if that's true, but even so, it doesn't seem like a particularly good thing to find on a coin! And given the other thread about CGS and their standards, I too share Stuart's .. surprise.

Was it a yellow label?

Edited February 28, 2013 by TomGoodheart

[Accumulator 52]

Well, when I searched for "what is pvc green on coins?" several entries claimed that eventually pvc residue will damage a coin.

Not knowing much about the chemistry of the whole process of 'pvc sweating' I don't know if that's true, but even so, it doesn't seem like a particularly good thing to find on a coin! And given the other thread about CGS and their standards, I too share Stuart's .. surprise.

Was it a yellow label?

I was given a coin album in 1968 and it had the old PVC pocket pages. As a lad I filled it up with pre-decimal currency collected from change. When I finally liberated the coins a few years ago the silver, in particular, was coated in a blue/green nasty, sticky deposit. I used acetone and it came off with ease.

[Peter 615]

I remember a cracking 1865 1/4d with a massive edge knock but still getting slabbed by CGS and Hey presto the edge knock disappeared in the slab.

It was in a London auction and went for £90 and reappeared in a slab for £150.

[Sword 1,477]

It can't be verd, as it's a silver coin. Most likely a deposit from an old PVC coin envelope. I'm not sure it's the responsibility of CGS to clean coins (other than a light dusting) before stabbing so it's really down to the previous owner.

.500 silver. The other 50% is vulnerable isn't it?

I was just going to ask about that, how do you get verd on a silver coin, if it's not, but a deposit, is it corrosive, and could it have been caused by living in the slab??

Not surprised at your shock though Stuart!

Yes, the non-silver 50% is mostly copper, so verdigris is possible.

Still getting over the shock that a humble 1922 3d would be slabbed!

I have done quite a bit of background search on Verdigris since my last post on the subject and agree with peck that verd is possible on 50% silver coins. Just type "verdigris" and "crown" into the past results in London Coins auctions and you will find photos of a number of wealth crowns with verd spots.

I came across an interesting article on ebay review which is written by a chemist and numismatist. It claims that acetone generally cannot remove verd but might remove other green deposits.

http://reviews.ebay.com/How-to-Remove-Verdigris-From-Coins?ugid=10000000017991989

Blaming CGS in this case is a bit harsh as the coin could have picked up a chemical deposit on the edge which was invisible at the time of slabbing and the green stuff would probably have developed whether the coin was slabbed or not. They can't clean each coin with chemical before slabbing as that will surely upset most collectors. What happen if some nice toning is removed by the "cleaning"?

On the subject of cheap coins being slabbed, I remembered that the London Coin site was selling some slabbed churchill crowns for about a couple of pounds about two or three yers ago. At the time, I wondered briefly why would anyone spend money to slab junk. Then I realised that it was probably done by CGS for training / practice.

[Coinery 1,156]

Acetone definitely removes light surface verd, IF you catch it in time, I've done so on dozens of copper and bronze coins in the past!

I guess my main point is CGS may very well have been unaware of the contaminate, whatever it is, but that doesn't detract from the fact that it was there, and with the potential to irreparably damage the coin over the long haul, which has always been a main concern of mine!

[Peckris 579]

On the subject of cheap coins being slabbed, I remembered that the London Coin site was selling some slabbed churchill crowns for about a couple of pounds about two or three yers ago. At the time, I wondered briefly why would anyone spend money to slab junk. Then I realised that it was probably done by CGS for training / practice.

Couldn't they have used 1967 pennies instead? Oh wait, then they couldn't have sold them at all

[Nick 329]

Acetone definitely removes light surface verd, IF you catch it in time, I've done so on dozens of copper and bronze coins in the past!

I guess my main point is CGS may very well have been unaware of the contaminate, whatever it is, but that doesn't detract from the fact that it was there, and with the potential to irreparably damage the coin over the long haul, which has always been a main concern of mine!

Apparently, the dreaded green can be copper carbonate, chloride or acetate. These three compounds are soluble in acetic acid, ethanol and alcohol (or water) respectively. However, knowing bugger all about chemistry - I can't vouch for the correctness of this info.

[Coinery 1,156]

It can't be verd, as it's a silver coin. Most likely a deposit from an old PVC coin envelope. I'm not sure it's the responsibility of CGS to clean coins (other than a light dusting) before stabbing so it's really down to the previous owner.

You do sometimes get green on hammered silver. I presume it's because the silver is mixed with copper to the correct fineness and sometimes you get a bit that's not so well mixed in and that's where the copper salts develop...

debased silver hammered!

[Coinery 1,156]

Acetone definitely removes light surface verd, IF you catch it in time, I've done so on dozens of copper and bronze coins in the past!

I guess my main point is CGS may very well have been unaware of the contaminate, whatever it is, but that doesn't detract from the fact that it was there, and with the potential to irreparably damage the coin over the long haul, which has always been a main concern of mine!

Apparently, the dreaded green can be copper carbonate, chloride or acetate. These three compounds are soluble in acetic acid, ethanol and alcohol (or water) respectively. However, knowing bugger all about chemistry - I can't vouch for the correctness of this info.

Where's Declan when you need him? He can generally pull a chemistry dissertation out the bag when you need one!

Acetic acid NEVER disappoints on verdigris!

[Peckris 579]

Acetone definitely removes light surface verd, IF you catch it in time, I've done so on dozens of copper and bronze coins in the past!

I guess my main point is CGS may very well have been unaware of the contaminate, whatever it is, but that doesn't detract from the fact that it was there, and with the potential to irreparably damage the coin over the long haul, which has always been a main concern of mine!

Apparently, the dreaded green can be copper carbonate, chloride or acetate. These three compounds are soluble in acetic acid, ethanol and alcohol (or water) respectively. However, knowing bugger all about chemistry - I can't vouch for the correctness of this info.

Where's Declan when you need him? He can generally pull a chemistry dissertation out the bag when you need one!

Acetic acid NEVER disappoints on verdigris!

This is true - however vinegar converts the verd into a dark stain (inactive) but also lightens the rest of the coin, which if it's copper/bronze is a possible great disadvantage. However, for a silver coin it shouldn't make a big difference

[Sword 1,477]

Acetone definitely removes light surface verd, IF you catch it in time, I've done so on dozens of copper and bronze coins in the past!

I guess my main point is CGS may very well have been unaware of the contaminate, whatever it is, but that doesn't detract from the fact that it was there, and with the potential to irreparably damage the coin over the long haul, which has always been a main concern of mine!

Apparently, the dreaded green can be copper carbonate, chloride or acetate. These three compounds are soluble in acetic acid, ethanol and alcohol (or water) respectively. However, knowing bugger all about chemistry - I can't vouch for the correctness of this info.

I have never tried to remove verd spots as I don't collect copper. Hence I have no practical experience in this but am now tempted to try out some experiments!Copper carbonate is a base and so will dissolve (react) with acid. Thinking more about it, you are right Coinery. Copper chloride is solube in acetone and I assume can be removed that way. (I shouldn't trust an article too readily without a bit more thought). Copper carbonate is insolube in water and I think is also insolube in acetone. However, if the verd has not eaten in, then acetone will at least act as a lubricant and should help to an extent. Acetone is an organic solvent and should be very good with plastic residues.

I still think that the main responsibilities of a TPG are to accurately grade the coin and to make certain that the slabbing process is not going to cause extra harm to a coin. It is a tad unrealistic to expect them to analyse the suface of the coin to see if there are any harmful substances on it. If it looks like a problem is developing, one should be prepared to crack the slab open to sort it out. If people are worried about the edge of the coin, then the NGC slab design shows the edge. I don't think slabbing is prefect by any means but I am of the opinion that a slabed coin has less chance of picking up damage (physcially or chemically). Slabed coins developing problems always raise eyebrows but a much much greater number are sitting safely (as far as one can tell ) in the slab.

[Coinery 1,156]

Acetone definitely removes light surface verd, IF you catch it in time, I've done so on dozens of copper and bronze coins in the past!

I guess my main point is CGS may very well have been unaware of the contaminate, whatever it is, but that doesn't detract from the fact that it was there, and with the potential to irreparably damage the coin over the long haul, which has always been a main concern of mine!

Apparently, the dreaded green can be copper carbonate, chloride or acetate. These three compounds are soluble in acetic acid, ethanol and alcohol (or water) respectively. However, knowing bugger all about chemistry - I can't vouch for the correctness of this info.

I have never tried to remove verd spots as I don't collect copper. Hence I have no practical experience in this but am now tempted to try out some experiments!Copper carbonate is a base and so will dissolve (react) with acid. Thinking more about it, you are right Coinery. Copper chloride is solube in acetone and I assume can be removed that way. (I shouldn't trust an article too readily without a bit more thought). Copper carbonate is insolube in water and I think is also insolube in acetone. However, if the verd has not eaten in, then acetone will at least act as a lubricant and should help to an extent. Acetone is an organic solvent and should be very good with plastic residues.

I still think that the main responsibilities of a TPG are to accurately grade the coin and to make certain that the slabbing process is not going to cause extra harm to a coin. It is a tad unrealistic to expect them to analyse the suface of the coin to see if there are any harmful substances on it. If it looks like a problem is developing, one should be prepared to crack the slab open to sort it out. If people are worried about the edge of the coin, then the NGC slab design shows the edge. I don't think slabbing is prefect by any means but I am of the opinion that a slabed coin has less chance of picking up damage (physcially or chemically). Slabed coins developing problems always raise eyebrows but a much much greater number are sitting safely (as far as one can tell ) in the slab.

Yes, I think the acetone is only acting as a cleaning agent, rather than chemically 'reacting' with the verd. I've only ever been able to remove the light beginnings of verd with acetone, rather than deep seated spots, and I genuinely think that was the case with the '22 3d. If it really was a plastic reaction from a flip, I would've expected the edge to have been the least affected? But by the by!

Anyway, as you say, it's unreasonable to expect TPG's to analyse the surface and atmospheric contaminants slabbed away with the coin. It's just always been something that has niggled me, and one of the first questions I ever asked of the slabbing process; wondering whether you can just lock a slab away, safe in the knowledge it's entombed and protected from environmental factors. In reality this is not the case and, knowing that CGS fiercely reject even the faintest traces of 'corrosion' (I know this from personal experience with them), it only leads me to believe FINALLY that coins can begin to deteriorate in slabs, as of course they can out of them!

Whether we will see more and more issues as slabs start to age, who knows but, in light of recent evidence (my verd 1951 penny taken from a US slab, and the uncomfortably verd-like edge on the 3d), I think there could be more to come.

Anyone know how old the first ever encapsulated TPGC coin would be now (and I don't mean the age of the coin inside )?

[Coinery 1,156]

PS you can spend it any more

'Wallet!' Only just got it, pies!

[Coinery 1,156]

Was it a yellow label?

No, regular slab issue for this one!

I've still got the cotton bud if anyone knows of a simple chemical experiment to determine the composition of the green coloured residue on it? What can you add to a copper component that guarantees a colour change or an explosion or something?

[Sword 1,477]

Was it a yellow label?

No, regular slab issue for this one!

I've still got the cotton bud if anyone knows of a simple chemical experiment to determine the composition of the green coloured residue on it? What can you add to a copper component that guarantees a colour change or an explosion or something?

Try adding ammonia solution. Any blue colour would indicate would indicate presence of copper ions. Copper ions react with ammonia to give blue copper hydroxide. (Further addtion of ammonia will give a deep blue copper complex but you haven't got enough substance on the cotton bud for this test)

[Coinery 1,156]

Was it a yellow label?

No, regular slab issue for this one!

I've still got the cotton bud if anyone knows of a simple chemical experiment to determine the composition of the green coloured residue on it? What can you add to a copper component that guarantees a colour change or an explosion or something?

Try adding ammonia solution. Any blue colour would indicate would indicate presence of copper ions. Copper ions react with ammonia to give blue copper hydroxide. (Further addtion of ammonia will give a deep blue copper complex but you haven't got enough substance on the cotton bud for this test)

Excellent, Sword, will give that a go! What would be the easiest source of ammonia...chemist?

I can get a 9.5% solution from boots! Strong enough, do you think?

Edited March 1, 2013 by Coinery