Verdigris...

[Sylvester 15]

Fior those that want to know what to look for, here is a coin that has just gone past the earliest stages of verdigris... (i'll be removing it shortly, both the picture and the verdigris).

Can you see it?

[Sylvester 15]

oh by the way Oli this post wasn't meant to be rubbing it in, but was for the benefit of another member...

[Emperor Oli 0]

Oh no, I didn't interpret it like that at all. If people can spot verdi gris early, that's good. I reckon that it's starting on the right wing of the eagle and above it in the dip created by the wing.

[Half Penny Jon 0]

Thanks Sylvester! I think that I have just got a few carbon spots, little devils! Btw, how can you remove verdigris?

Edited June 26, 2004 by Half Penny Jon

[Emperor Oli 0]

I think it's nigh-on impossible to remove verdi gris from coins but if anyone knows, please share! i've tried soaking one of mine (19sixtysomething 3d) in nail polish remover (acetone) but it doesn't seem to lift it.

[Sylvester 15]

Well abopve the right wing is one place i'm definately watching, but if you look above the R in QUARTER...

If caught early enough it can be removed by a gentle scratch with a fingernail, but be careful cos you can scratch the coin... but of course if you leave it then it'll just ruin the coin further, so it's a no win situation. A small scratch near a spot or a bverdigris encrusted coin.

The best method is prevention...

As i can figure it out...

CO2 + H2O + Cu = CuCO3 + H2

So eliminate the Carbon dioxide or the vater vapour and verdigris shouldn't form... So don't breath on you coins, a houseplant would (should), be a good thing to have as it will remove CO2 from the atmosphere...

Then the only thing you have to worry about is carbon spots, or copper oxide (yes those little brownish black spots)... which is just as bad to be honest as it's corrosion all the same.

But then again so is toning on silver coins...

[Master Jmd 50]

would there be any way of removing the oxygen from coin capsuals?

[Emperor Oli 0]

Unless you could get a vacuum pump to somehow suck the air out or find a chemical to turn oxygen into something relatively inert like xenon, then no.

[Sylvester 15]

Probably, i think the best way of sealing a coin in to a capsule would be in a laboratory...

If the coin and capsule was placed in a gas chamber, and the oxygen was removed and was replaced by a noble gas like helium or argon then the coin could be put in the capsule and it would be oxygen free and since helium etc. are inert then no further reactions should be possible.

I haven't got a periodic table on me but any gasses in the same group as helium, so neon, argon, krypton, xenon, should all be okay... i'd stay away from radon though as it's radioactive...

I'm sure helium is the best bet all round it is probably ascertainable cos they use it for balloons at parties.

[Half Penny Jon 0]

Probably, i think the best way of sealing a coin in to a capsule would be in a laboratory...

I will have to make do with my warm-ish bedroom.

[Half Penny Jon 0]

This morning I suddenly remembered that I had put away two years ago a small selection of predecimal circulated coins mostly Elizabeth II and George VI. Anyway, I remember that when I put them away one of the coins (a rather worn 1893 penny) had a few spots of verdigris on it. Two years ago I was unaware of verdigris and it's effects.

When I opened the jar this morning, I found that the coin that my 1893 penny was all virtually green, and about 50 other bronze coins had been coated in the crusty green slime! Just shows how easily it can spread to loads of coins from just a few minor spots.

[Sylvester 15]

When I opened the jar this morning, I found that the coin that my 1893 penny was all virtually green, and about 50 other bronze coins had been coated in the crusty green slime! Just shows how easily it can spread to loads of coins from just a few minor spots.

Exactly... the stuff spreads and it's very unforgiving. One spot and away you go. Obviously wherever you had put them has exactly the right conditions for verdigris to form and spread.

Hang on it wasn't a plastic jar was it...? you mentioned slime (that's not just verdigris i'm thinking).

[Half Penny Jon 0]

It was an old glass coffee jar which was quite humid methinks.

[Half Penny Jon 0]

There is no way to remove the full-blown kind of verdigris (the crusty green stuff) without actually harming your coins. However, I have discovered that you can use WHITE SPIRIT to remove the waxy green colour which is the precursor to verdigris (just wash the coin gently with soapy water after). I hope this helps some of us solve our verdigris problems. So basically check your coins on a regular basis and if they have the precursor to verdigris, it can be taken straight off! At last a solution which will not harm our coins!

Edited July 21, 2004 by Half Penny Jon

[Chris Perkins 223]

I have been known to wash waxy bronze/copper it soap and water too but I always fear that the action of getting them wet may do harm! I suppose that probably isn't the case if they are dried properly.

[Sylvester 15]

I have been known to wash waxy bronze/copper it soap and water too but I always fear that the action of getting them wet may do harm! I suppose that probably isn't the case if they are dried properly.

I wonder if Acetone is better?

Wash them with that... then rinse them with distilled water (you can get that from the chemists), then after that pat them dry on a soft cloth, don't rub.