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 Replies: 9 / Views: 1,696 |
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Pillar of the Community
 Australia
2502 Posts |
Hi all, Another coin I'm not happy with is this 1951 PL halfpenny. Not a bad looking coin for 71 years old, but seems like someone who handled this coin in the past left a fingerprint on both sides as both a memento and a challenge to me  . I gave it the obligatory soaking in acetone, but was too scared to apply a Qtip for fear of blemishing the tone of the piece. A. Is there another method worth trying? B. Concensus on whether it would be better to leave it as it is? Thanks in advance, as always your comments and advice are appreciated. Cheers TT   The Ox moves slowly, but the Earth is patient.
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Moderator
Australia
16808 Posts |
Human fingerprint oil is high in sulfur-containing chemicals. These ornganosulfur compounds react quite quickly with lustrous copper, causing irreversible darkening as copper sulfide forms.
In other words, "you can't".
If you know that you've recently accidentally touched a coin with your finger, the fingerprint oil you just put there can be safely removed from the surface of a coin using acetone or similar solvents, before the chemical reaction can happen and the fingerprint becomes visible. But once the print "develops" and becomes visible, it's too late. Acetone won't help.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Pillar of the Community
United States
7613 Posts |
Copper and bronze coins just don't seem to do well with restoration attempts. The natural luster and surfaces are just too sensitive to chemical assault.
I'd leave well enough alone and be happy with its current appearance.
Just my two-cents. Others may have differing opinions.
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Pillar of the Community
 Australia
2502 Posts |
Quote:
Human fingerprint oil is high in sulfur-containing chemicals. These ornganosulfur compounds react quite quickly with lustrous copper, causing irreversible darkening as copper sulfide forms. Thanks Sap....always good to get the technical detail behind it. Quote:
I'd leave well enough alone and be happy with its current appearance. Thanks westernsky, that's the way I'm headed Cheers TT The Ox moves slowly, but the Earth is patient.
Edited by ttkoo
07/04/2022 6:20 pm
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Bedrock of the Community
United States
19118 Posts |
Unfortunate. Yes, I agree with Sap.
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Bedrock of the Community
United States
94367 Posts |
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Moderator
United States
94786 Posts |
only when the print is very new and fresh can it be carefully removed, but they are like a stain on a white shirt, once it is set, it is permanent
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Pillar of the Community
Australia
2502 Posts |
Thanks Coinfrog, Dearborn and ijn1944. Leaving it be  The Ox moves slowly, but the Earth is patient.
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Pillar of the Community
Canada
5238 Posts |
The only plus is that since you have the fingerprint you might be able to identify the culprit.
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Pillar of the Community
Australia
2502 Posts |
Quote:
The only plus is that since you have the fingerprint you might be able to identify the culprit.  The Ox moves slowly, but the Earth is patient.
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Replies: 9 / Views: 1,696 |
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Posted 07/04/2022 12:13 am
