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 Replies: 26 / Views: 2,853 |
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Bedrock of the Community
Australia
21788 Posts |
I suspect that the coin has some kind of organic partly water soluble coating on it. The water seems to have softened and expanded it. Does the coin have a slimy feel when wet?
That little white ring that Sap spotted suggests to me that the coin may have been laquered, perhaps as a method of preserving it. I have sprayed acryllic laquer on a coin myself by way of experimentation.
Try soaking it in kerosene, then methylated spirits, then acetone, then let it dry naturally.
All of the abovementioned are organic solvents, but the methylated spirits has a hydroxide radical (OH)-, which is the same as water when it splits into a H+ and an (OH)- radical, which explains why water is a good solvent for so many things.
The other two are purely organic solvents. The high volatility of the acetone will eliminate the need to dry it. So will the methylated spirits.
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Rest in Peace
United States
9104 Posts |
Could it be like the electrolysis caused by dissimilar metals in contact?
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Bedrock of the Community
Australia
21788 Posts |
biggfredd: I don't think so. bobbbyhelmet has not reported any loss of metal from the coin.
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Rest in Peace
United States
9104 Posts |
For the right side up folks, methylated spirits = denatured alkyhaul, commonly 90% ethanol and 10% methanol.
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Rest in Peace
United States
9104 Posts |
Quote:
bobbbyhelmet has not reported any loss of metal from the coin. Maybe it's the other coins losing metal. |
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Pillar of the Community
 United Kingdom
2838 Posts |
Well, this is it a further 24 hours later:  Quote:
I suspect it's some kind of coating or perhaps artificial patination that's coming off. This is certainly a possibility but (not sure if I'm correct here) wouldn't that be dark in colour? Quote:
What's the little white ring near the rim at 5 o'clock? It's looking suspiciously like a filled hole to me. Optical illusion - it was just a build up of the substance on and around an 'O' in the reverse legend. Quote:
From the "before" pic, it looked clean enough - what made you decide to soak it? It was clean-ish but I thought the details could be brought out a little more with a bit of a soak. Quote:
Chemical reaction with the other coins and the water? This had crossed my mind also but as the above proves cant be a factor. Quote:
My guess would have to be a very old coating of wax that you didn't notice before soaking. Again, definitely a possibility, I could have missed it if it was old and worn thin and I think I'm right in saying some weird and wonderful concoctions were used as coatings in the past. I will attempt to do as you say and dry some of the substance out. Quote:
I suspect that the coin has some kind of organic partly water soluble coating on it. Again, very possible, whatever the coating is it could be over 100 years old so could be some kind of weird and wonderful home made concoction. I should be able to get my hands on some acetone pretty easily, not sure about the other two but will try. Quote:
Could it be like the electrolysis caused by dissimilar metals in contact? Still no loss of metal or detail from the coin. I should also add that the coin does not seem to be changing colour. I also think it may have been harshly cleaned in the past. It does not feel slimy when covered. I'll keep you all posted  Edited by bobbyhelmet
01/24/2012 08:34 am
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Pillar of the Community
United Kingdom
2838 Posts |
Quote:
Maybe it's the other coins losing metal. Hadn't even thought of that - that would have been an interesting reason for it. Its soaking alone now and still happening so I guess we need to discount it. |
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Pillar of the Community
United States
509 Posts |
Scrub the heck out of it with a soft toothbrush or something similar.
Run under water for a long time.
Repeat step 1.
Then run under water for a while longer.
Repeat step 1.
Then soak it and see what happens.
The purpose is to remove all water soluble contaminants.
My first thought would be the coin composition itself was causing this, but contact with other minerals (natural or applied) could play a role.
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Pillar of the Community
United Kingdom
2838 Posts |
Done the above and got some of the 'white stuff' out and currently drying - lets see what tomorrow brings!
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Bedrock of the Community
Australia
21788 Posts |
Actually methylated spirits also has about 0.2& puradine in it.
If you don't believe me, put a tiny spoy of methylated spirits on the end of your tongue. It will feel as if someone is sadistically trying to bore a hole through it!
I tried that trick once as a kid. NEVER again!
Puradine is quite poisonous, but it won't kill you in the amounts that are added to ethanol to make methylated spirits. It is added to stop people from drinking the stuff.
The methyl alcohol is the dangerous one that caused so much trouble with people drinking wood alcohol. It issometimes known as 'ginger jake' during the era of Prohibition. That is why the puradine is there.
Famous saying:
"Make moonshine while the hay grows!"
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Rest in Peace
United States
9104 Posts |
Quote:
I should be able to get my hands on some acetone pretty easily, not sure about the other two but will try. Kerosene is often at petrol stations, commonly used in heaters or lanterns. Methylated ghosts should be in the beauty aids or pharmacy. |
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Rest in Peace
United States
9104 Posts |
Various booze is made in high school labs, with added phenylthaline. Didn't always stop kids from drinking it, but when a kid took potty breaks every few minutes, they knew the culprit.
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Pillar of the Community
United Kingdom
2838 Posts |
Well I dried some of the stuff off over night and although I couldn't be 100% certain it had the look of some kind of wax or protective coating. Precious little of it remained after drying out but when I rubbed it into the bottom of the container I used to dry it it left a shine and a semi-water resistant coating. I guess the key here is the fact that it was only semi-resistant. I would have noticed it on the coin otherwise as it was going in ans out of the soak. Water just runs off wax like it does off a ducks back. Also, after scrubbing the front and the back of the coin thoroughly yesterday the only place the stuff is still leaching from is now the coin rim. So, as far as what conclusions can be drawn I guess it was just a previous owners coating that caused the odd effect. Who knows what it was and when it was applied, some of these coins have been moving from collection to collection for a couple of hundred years. Thanks for everyones input  |
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Pillar of the Community
United States
2044 Posts |
I suggest soaking for a little longer if some of the substance is still on the coin, on the rim as you said.
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Valued Member
Canada
114 Posts |
I've had something similar happen with some poor quality coins I had. They were so bad that I just used them for experimenting different cleaning methods. I tried electrolysis on some and soaking some in wd-40. Only a few of them started "leaking" the white stuff. I would assume that whoever you bought them from tried partially cleaning them to see what he had and it could either be some residual oil that was not scrubbed off or was stored in the dirt because it is not water soluble, or some impurity released by the electrolysis. Or if you scrub them with soap between soakings, you might not be rinsing well enough.
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Posted 01/24/2012 07:28 am
