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 Replies: 23 / Views: 3,835 |
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Pillar of the Community
3352 Posts |
I'm a bit confused why all circulated coins don't have fingerprint-marks all over them? (or do they?) ... I try very hard to handle my coins by the edges and/or try even harder not to touch them at all with my bare hands, because I'm afraid that I'll burn a nasty ol' fingerprint into their pretty shiny surfaces ...... but then I thought to myself, "Self ... why doesn't every single coin in your wallet have nasty fingerpint-marks riddled all over them?" (Self didn't know the answer) ... => Do any of you Big-Shooters know why this is?  Edited by stevex6
11/11/2011 2:24 pm
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Pillar of the Community
 3352 Posts |
Anyone? .... anyone? .... Bueller?
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Pillar of the Community
United States
4132 Posts |
It's because they get handled so much that they're completely coated in human sebum.  When you leave a fingerprint, it only leaves it where the ridges are and leaves empty spots between, creating the contrast. But if you handle a coin a bunch it ends up completely coated in grease. |
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Pillar of the Community
3352 Posts |
hmmmm, maybe I should stop putting them in my mouth?
Thanks ... now that I think about it, I'm sure you're correct ...
so the flip-side is => it's better to handle your coins a "whole bunch", rather than just once!?
Nah, I think I'll stick to not handling them with my greasy, human-sebum, mung-fingers!
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Pillar of the Community
Australia
2830 Posts |
I collect old, circulated coins, and I have always assumed that the black crud that contrasts with the design-elements of my coins is a mixture of:
sebum, and animal grease (from food), and other unspeakables, holding together soot, dirt, and goodness-knows what else.
I don't put my coins in my mouth, but each to his own ...
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Pillar of the Community
3352 Posts |
mmmmmmm, dirty, sooty goodness ... just kidding (no mouth)
Thanks for responding
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Moderator
 United States
23522 Posts |
You guys are making me want to go barbecue some nickels.
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Pillar of the Community
United States
4132 Posts |
If it's any comfort, copper, silver and their alloys are self-sanitizing. Within a few hours of being handled by some snotty, germ-infested kid, a coin is sterile.
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Valued Member
United States
187 Posts |
Quote:
You guys are making me want to go barbecue some nickels. SuperDave,I tried to slow smoke some nickels once,but I just couldn't get them lit.  |
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Bedrock of the Community
Australia
21786 Posts |
Human skin exudes a natural oil to keep it supple.
If a brand new copper surface comes into contact with fingers once only, the prints are left behind and the residue oil, over time, will react with a copper surface. Visible finger prints will be left behind. These finger prints can be impossible to remove, because the oil in the skin is really a type of fatty acid, and has reacted with the metallic surface.
If a coin is handled a great deal, all these finger prints from many people get merged into each other, evenly.
To demonstrate that skin exudes an oil, put your hands in a mild caustic solution. The result is that your hands will feel soapy. What has happened in this case, is that the oil has reacted with the OH ions of the alkaline caustic solution, and actually have produced a sort of 'soap'.
What has really been produced is that an insoluble. oil has been converted into a soluble oil, which is what a soap really is. your skin will feel dry because the oil has beeen strippd out of your skin.
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Pillar of the Community
3352 Posts |
"it puts the lotion in the basket"
... name that movie
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Pillar of the Community
United States
4132 Posts |
Quote:
To demonstrate that skin exudes an oil, put your hands in a mild caustic solution. The result is that your hands will feel soapy. What has happened in this case, is that the oil has reacted with the OH ions of the alkaline caustic solution, and actually have produced a sort of 'soap'. Which is why bleach feels slippery on your hands. |
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Pillar of the Community
United States
4778 Posts |
Also sometimes when someone holds a bunch of coins in their hand, alot of the coins don't really come into direct contact with the skin (since the coins are usually in a pile).
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Pillar of the Community
United States
3278 Posts |
Isn't sebum earwax, come on your me out
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Pillar of the Community
Australia
2830 Posts |
quote from http://en.wikipedia.org/wiki/Sebum#Sebum - "... Sebaceous glands secrete the oily, waxy substance called sebum (Latin, meaning fat or tallow) that is made of fat (lipids), wax, and the debris of dead fat-producing cells.  In the glands, sebum is produced within specialized cells and is released as these cells burst; sebaceous glands are thus classified as holocrine glands. Seborrhoea is the name for the condition of greasy skin caused by excess sebum.[4] Sebum is odorless, but its bacterial breakdown can produce odors. Sebum is the cause of some people's experiencing "oily" hair,[5] as in hot weather or if not washed for several days. Earwax is partly composed of sebum." Sebum is, usually, the stuff that becomes "fingerprints" at a crime scene. |
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Pillar of the Community
Australia
7096 Posts |
If you have ever been to a stripper bar in Asia you would NEVER put a coin in your mouth |
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Replies: 23 / Views: 3,835 |
Posted 11/11/2011 5:38 pm
