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Waredu
Valued Member
United States
397 Posts
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Primarily - can it spread from one coin to another?
I know verdigris is caused by any one of several different chemical reactions - similar to rust. I know copper is a highly reactive metal - and the different things it reacts with cause different types of verdigris.
What I don't know is if it spreads.
I'm assuming that if a cent is developing verdigris in one environment and I put a second cent beside it - the second will also develop, since the environment hasn't changed.
But what if I removed the corroded coin and put it in a different environment beside a clean cent? Will the process continue and infect the other coin as well? I know infect is a somewhat imprecise term - but it gets my meaning across.
I plan on tossing my 1959-1982 copper cents I get from roll searching into a glass 5-gallon water jug (assuming I can find some). I'll toss in a little package of desiccant every once in a while and keep the jug in a closet inside the house - where the heat and humidity are somewhat more controlled than, say, my garage.
None of these coins are anything special at the moment - but I predict that my grandkids (assuming my kids have kids of their own someday) will appreciate having them to go through - if nothing else, they will just be old coins and a bit of history.
But I don't want one or two coins with verdigris slowly turning the entire pile into green dust. Am I right to be worried?
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Pillar Of The Community
United States
10042 Posts |
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Pillar Of The Community
United States
10042 Posts |
I should also say....welcome to the forum! If you have any questions regarding verdigris, I'd be happy to answer them. I'm a chemist and I've been studying verdigris heavily for a couple of years now. I'm even in the process of writing an entire book about it for numismatists.
Lincoln Cent Lover!VERDI-CAREâ„¢ All Metal Conservation Fluid http://www.verdichem.com
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Moderator
United States
7122 Posts |
It appears that my remarks in the grading forum have opened a few eyes. This is the second or third thread in the last couple of days dealing with verdigris, Thad is absolutely correct, verdigris is contagious to other coins.
it will not stop unless it is stopped and it will damage the coin that its growing on if allowed to continue unchecked.
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Valued Member
United States
397 Posts |
Ok, is there a way to inhibit growth? I know Thad's products, Verdi-Gone and Verdi-Care (not sure if those are ©, ®, or ™)will stop it and then conserve the coin - but none of these coins are really worth such treatment at this point. Right now, they're worth 1¢ - but in 50 years or so, long after I am dead and gone, they may be worth more (especially if the melt ban is lifted). Any that are still full red get set aside anyway.
I know, for example, how to inhibit rust - just move it to a more arid environment. The damage is done, but it can be slowed, if not stopped, simply by changing the environment. Rust is simple though compared to verdigris. While I enjoyed chemistry in high school and college - that was more than 20 years ago now.
So...would a more arid environment, in the dark, inhibit verdigris? Or should I just send the infected coins back to the bank?
And thanks for the welcome! I've been reading here for so long now I feel like I know some of you - even though I only joined a short while ago :)
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Valued Member
United States
51 Posts |
BadThad,
What is the growth rate for verdigris? How long dies it take to infect another coin, relitively speaking?
Thanks,
Cindy
And WELCOME Waredu. This is a great place.
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Valued Member
United States
420 Posts |
Thad, if you need "live" cases to study, my latest rolls came with 2 attached that I swear actually made a "slurp" sound when I pried them apart, still wet, all green, in a bag separated from everything else now
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Pillar Of The Community
United States
10042 Posts |
Quote:
Ok, is there a way to inhibit growth? Yes! A completely dry and air-free environment. Verdigris requires only three things to grow: copper, air and water. Light has no effect. Quote:
Or should I just send the infected coins back to the bank?
Probably your best bet. If you really want the coins to last for 50 years. The best thing to do is to bake them at a low temperture (<125°F) for an hour or so to remove all traces of moisture. Then transfer them (while still warm) to a ziplock and then put that ziplock into a very well sealed container with a desiccant pack. They should keep for a long time like that.
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Valued Member
United States
397 Posts |
Thanks Thad. I appreciate your knowledge.
So, just so I'm straight on this - verdigris requires moisture? Air is composed of a lot of elements, many of which react with copper. I can't really create a vacuum in my house, but I can make sure I put the coins in an extremely dry environment, especially with desiccant.
If I can remove 1 of the 3 and that will stop the verdigris, that will work.
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Valued Member
United States
467 Posts |
Question for Thad. I have several clear bank roles of 1987D and P. 2 of the roles have 1 coin each that is covered down about 1/3 in the role. Too late or open the role and get the good ones in a plastic tube? What would have caused it as the roles are air tight in the middle?
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Pillar Of The Community
United States
10042 Posts |
Quote:
So, just so I'm straight on this - verdigris requires moisture? Without water verdigris cannot form. However, it only take a few molecules to ruin the party. If you get rid of most of the water and protect well from air, the formation rate is negligible.
Lincoln Cent Lover!VERDI-CAREâ„¢ All Metal Conservation Fluid http://www.verdichem.com
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Pillar Of The Community
United States
10042 Posts |
Quote:
Question for Thad. I have several clear bank roles of 1987D and P. 2 of the roles have 1 coin each that is covered down about 1/3 in the role. Too late or open the role and get the good ones in a plastic tube? What would have caused it as the roles are air tight in the middle?
Rolled coins come from bulk bags. Sometimes they are not even solid date. The corroded coins must have been put in there when they were wrapped. It's NEVER too late to break those rolls and get rid of coins that have verdigris. Eventually, the corrosion will travel down and corrode all of the coins. Separate those infected coins!
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Posted 07/22/2010 9:23 pm
