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 Replies: 27 / Views: 3,599 |
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Bedrock of the Community
United States
19966 Posts |
What's the composition of that coin?
It sure looks like it had contact with a ferrous (iron) metal or the coin has iron in it.
Oil has no "pH". In order for a pH to be present, the solution must be aqueous. However, you can say that an oil is either alkaline or acidic in character. Olive oil is somewhat acidic due to the natual organic acids present. That's why it will dissolve verdigris.
I think this coins a gonner, the corrosion is just too bad.
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Pillar of the Community
 United States
2669 Posts |
It's bronze. How long of contact would it have had with iron to do this much damage?
Is mineral oil the same as mineral spirits?
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Bedrock of the Community
United States
19966 Posts |
Hard to say, depends on temperature and humidity.
No, mineral oil and spirits are not the same. I don't think either would have any effect. A strong EDTA solution might do something, about all I can think of short of acid. I don't think EDTA is available to consumers.
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Pillar of the Community
United States
2669 Posts |
I have some Vulpex Liquid Soap and Biox Conservation Liquid (supposedly good for removing corrosion). I have some lincolns that are completely covered that I was going to experiment on. Ever hear of these and how well they may work? Link to them: http://www.dirtyoldcoins.com/shop/s...s/index.htmlI also have this conservation mix that's supposed to be slightly stronger than their mix #1 which helps with bronze disease: http://nobleromancoins.com/product_...2609e7b013d3I also have straight lye. Maybe I'll just mix 'em all together! Watch for me on the news.  |
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Bedrock of the Community
United States
19966 Posts |
Those are all what I classify as harsh cleaners. They seem to be intended for use on ancient coins. It always scares me when they talk about "scrubbing" a coin. LOL
Do some digging and see if you can find any EDTA (ethylene diamine tetraacetic acid ). You might be able to remove the iron by chelation.
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Pillar of the Community
United States
2669 Posts |
From what I've been able to find, it's relatively expensive. What about activated charcoal?
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Pillar of the Community
United States
2669 Posts |
Oh - and yes, I have those other cleaners for ancients. I have not yet tried them, however. The first one says it will work in 1-8 hours, and both say "will not harm patina of coin". I suppose a patina of 1000 years would be a bit harder to damage (or damage harder to detect) than one of only 100.
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Pillar of the Community
United States
5318 Posts |
"What about activated charcoal?" I think that simply binds to and isolates some active compounds, which is a good thing if you've ingested something harmful. I don't think it will not actively dissolve verdigris from a coin. Perhaps BadThad can best answer here, but something like verdigris would need something reactive enough to swap those chemical bonds already present?  I'm not a chemist here, but it's a fun subject to ponder. |
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Pillar of the Community
United States
2669 Posts |
Yes, it binds to and isolates, especially if taken internally. Externally, it again pulls out impurities (i.e. a poultice of activated charcoal over a wound, or even over the liver on unbroken skin, will pull out impurities). So after the next 'flush', less of the impurities would remain. I suppose the question is, if the object containing impurities is not live, what would it do? And what exactly would be considered an impurity? I would guess any bronze disease or verdigris would be bound to first, but what about normal coin composition? Where's our local chemist?!  |
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Bedrock of the Community
United States
19966 Posts |
Charcol will do NOTHING for this. It will bind and trap organic molecules only, i.e. water filtration. What it looks like you have is an iron deposit on the coins surface. Now, just to confuse you, iron will react with charcol (aka carbon) at high temperatures. It's a common way to purify iron to remove the oxides (rust): 2Fe2O3 + 3C ==> 4Fe + 3CO2 However, they do this reaction in a blast furnace, which would melt the coin into nothingness. LOL Try the EDTA, looks like you can buy it as a vitamin supplement. Just dissolve it into a small amount of distilled water and soak the coin: http://www.puritansale.com/pages/fi...&ci_sku=8931Lincoln Cent Lover!VERDI-CARE™ INVENTOR https://verdi.care/
Edited by BadThad
06/15/2008 10:18 pm
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Pillar of the Community
United States
2669 Posts |
Thanks, that's a bunch cheaper than where I was looking. If the never-used colon-cleanse kit laying around here somewhere doesn't have some in it, I'll go get some from there. I'll keep you posted.. thanks a lot  |
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Bedrock of the Community
United States
20753 Posts |
Carefull there BadThad. Your scarring off those that don't want to remember school, it is out for the Summer you know.
My suggestion is you have a coin that is fairly well shot, so to speak. In other words mostly now valueless. This is a great coin to experiment with on getting rid of such contaminations.
To start with keep records of your attempts. Might be a book someday.
First try the easiest and cheapest methods. Soaking in Distilled Water. If this fails, and probably will, try other household items. Oddly enough many people swear by Lemon Juices, Tomato Juices, Lime, etc. Some have used Vinegar, boiling in just tap water, tap water that has gone through a water softener.
The most commonly used purchased item is Acetone. Allowing to soak in that for a period of time occationally works.
The problem is that the metal of that coin has already combined with something to form a coating on the coin. The removal of that substance will take the metal of the coin, now combined with something, off as well. This would probably leave pits, scars, etc on the coin.
As I said, consider this coin basically a great test coin for possible future savings of a coin.
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Replies: 27 / Views: 3,599 |
First Page
Posted 06/13/2008 12:14 pm
