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 Replies: 8 / Views: 1,084 |
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Valued Member
United States
327 Posts |
I have a question. The lot of world coins I bought are really, really filthy. I mean, beyond even usual circulated grime. Some are just normal circulated dirty, some are greasy/oily and some, so help me, appear to have been scraped from the floor of a poorly maintained gas station restroom. A few minutes of sorting produces grimy, nasty fingertips with an unpleasant odor.  I took several of the corroded encrusted ones (I'm not making this up) that were unrecognizable and threw them in the rock tumbler with some water and aquarium gravel, which is what I use for my metal detecting nasties. It cleans them up, but now they look, well, cleaned (which these turned out to be common low value coins)so I know this isn't the solution. What, if anything, do the members here do for coins like this? A search for cleaning reveals multiples of "DON'T DO IT!11!", which I understand is the norm, but really, who wants to leave the nasty oil, grease and unidentified (and probably germ filled)film of grime on their coins? I know others here must have gotten similar lots before. Help a newb out here! |
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Pillar of the Community
Egypt
3470 Posts |
 To CCF. Try soaking them in a 100% pure Acetone (not that used for nail pollish) for 15 minutes then rinse with distelled water. Hope that other members would correct me if I was wrong |
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Pillar of the Community
United Kingdom
1077 Posts |
If they are low value and greasy I would soak them in some warm soapy water first to get the oil and dirt off. Don't scrub them with anything more than your fingertips though.
Any more stubborn stains you could then try the acetone.
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Pillar of the Community
United States
860 Posts |
The pure acetone will kill any bacteria, viruses, or fungi ( with the exception of some spores) on the coin surfaces. Actually the soapy water will give almost as good results, except on badly corroded coins.
Jim
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Pillar of the Community
Australia
2830 Posts |
G'day, I agree with 'Breeze.
I have never used acetone, but I bought a bottle earlier this year. I leave it in my Quarantine zone, where all my dirty coins can see it. I'm hoping that it has some shock value ...
I agree with SPQR about the unspeakable gunk accreted to some coins: the concept of "biohazard" comes to mind. Such coins are pretty much worthless, for that very reason, so they make good subjects for a bit of research.
A technique I have tried, with some success:
freeze coin, and then quickly use bamboo toothpick to get gunk out of legends - these areas are resistant to rubbing between fingertips. If the gunk is still frozen, it often pops out as a sizeable lump, without much pressure.
I've used 95% alcohol (metho) as a soaking agent, which was disappointing, but at least I moved past my fear of catching an infection.
A comment on grammar: never, never, NEVER, put these phrases in the same sentence:
coin;
rock tumbler; and
gravel.
Peter in Oz
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Pillar of the Community
United Kingdom
1077 Posts |
I like the freezing idea to solidify the gunk, I will have to try that.
I too have on occasion used a bamboo skewer with the end frayed to clean gunk out of the detail areas with good success. It does not seem to scratch at all.
You have to be careful you don't scrape the surface with the grit you are removing though. This is also true even when using fingertips.
I would only do it on a coin that is already extra fine or below.
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Pillar of the Community
United States
5318 Posts |
Quote:
the concept of "biohazard" comes to mind. I see a lot of gunky coins in dealer's bargain buckets. Dirt, oil, and small particles of metal combine to make the grime that coats my hands after a long search. It usually has a strong odor of copper, and therefore I think few microbes will survive--US currency also uses copper-based ink to reduce the spread of disease. Annoying, but not something to worry about. I remove this stuff with denatured alcohol...it has few health concerns than acetone. |
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Valued Member
 United States
327 Posts |
Some good suggestions here, thank all! I read about the Acetone earlier, but one whiff gives me a blinding headache , so I think I'll pass on that, thanks very much. I might try mineral spirits; I've used it to remove cosmoline (a thick gunky grease used by the military to preserve metal objects for long periods of time) so it should remove fingerprint oils and whatnot. I hadn't thought of it before now though  . I'll test on some US clad and zincoln pennies for results.  @ Peter in Oz.... Yes, I usually reserve the gravel and tumbler for the change I scavenge up metal detecting. I know it's hard on the coinage but cashiers look askance at me when I hand them nasty skanky change, but an hour in with the gravel and it's nice and shiny. |
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Valued Member
Australia
432 Posts |
Yeah I too have used the warm soapy water and bamboo (tho I use a chop-stick, so I can carve whatever shape I need; normally a point or a small chisel), however I have heard that Olive Oil can also do the trick...
While I am here, any hints on Cleaning ZINC (Zn - 100%) coins? Relectant to jump in without having more input and more research!
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Replies: 8 / Views: 1,084 |
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Posted 11/01/2008 6:17 pm
