Fingerprints on Proof Coins, and How I avoid them on mine..without cotton gloves

Agreed. Sometimes we forget coins are metals and metals don't get marked up and damaged at the slightest touch

 

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OK, so it seems this thread is not an early April Fool's joke, just another numismatic tradition biting the dust. We don't have that many of them folks, and at some point we won't have any left.

 

Yes it will! I did it to one of my proofs because of something on the surface of one silver coin. I used a cotton swab, and just lightly touched the coin.

 

Oh hurry April (bloody cold)l.........I just ordered up some of OP's stuff.......ain't gonna apply no cotton swabs, just some 'meaty' mitts. Things favorable....

 

Your comment made me think about something that almost never gets mentioned in grading reference materials:

How much weight is given to the edges of a coin in the grading process?
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Hypothetical Example: I'm a TPG grader. A Morgan Dollar arrives at my desk, It appears as if this coin is perfect, I double check both the obverse and the reverse and I evaluate the strike, color, luster and condition and it warrents the1st ever MS-70 grade my reputable company has ever given. But oh wait.....I triplet check it just to be sure it's not a counterfeit.. II am counting the reeds to be certain that it has exactly 133 reeds.
Oh no......
The edges of this coin have two ridges of a barely perceptible brown fingerprint spanning two reeds of this dollar....

Must I mark this coin down to 69?

 

Good point. However, I'd guess there's not a lot of reed counting by graders unless they are doing certain varieties or unless they see something else that makes them suspicious of authenticity. Reed counting could be automated fairly easily. Would need a computer-controlled turntable, slit lamp and computer-connected photo-detector. However, at least a quick look at the edge is probably routine. Another reason not to press the flesh even to edges of AU, MS and PR coins.

Cal

 

No gloves for me...can't feel the coin with them on...I work with clean hands, over clean satin cloth, and use a new and clean credit card to flip and move the coin around. Never a problem with hairlines or finger prints.

 

Start looking at the edges of coins. You'll find all sorts of things. Now, pretend you really are a professional grader...

1. How much are you going to deduct for a Silver Eagle with a small stain on the edge?

2. Have you ever looked closely at the rims of a Morgan dollar? How much do you think is deducted for all the nicks?

3. When a coin is put into a non-edge view insert, how much of the edge is even visible? How much of the rim. Take a look at some TPGS slabs.

What is the difference between some toning "overlap" and a finger print or stain?

From what I know, it seems that things like mount removals, rim files, actual detracting damage, and corrosion are usually enough to rate a "details" label.

 

Gold and silver is in the range of 2.5-3.0 hardness by the Mohs scale. Although organics are usually not measured the same as minerals, the estimate for cotton fibers ( depending on the species) is generally from 3.5- 4.5 on the same log scale., so with pressure applied could cause damage. I am sure most have seen a coin struck-through of fibers imprinted on a coin. This was minting pressure, but if the fiber was softer than the coin metal, the imprint would be more like grease is. If only the tips of cotton fibers is used like a brush, the flexibility acts as a softer material. But to just say cotton Q-tips will cause no harm ( some assume all pressures) is not an accurate statement. I would not use them as I too have seen damaging actions. Jim

 

Jim said: "But to just say cotton Q-tips will cause no harm (some assume all pressures) is not an accurate statement. I would not use them as I too have seen damaging actions."

Q-tips can leave hairlines even when used carefully and correctly by an experienced Q-tipper such as ... In many of these cases it is because the cotton picked up some unseen foreign material.

 

Aye, there's the rub.
Cal

 

And don't forget the flowlines, they are like little razors on a microscale and are damaged VERY easily.

 

Acetone MSDS

https://www.fishersci.com/shop/msdsproxy?productName=AC177170010&productDescription=ACETONE

 

Before someone ends up dead mimicking irresponsible behavior posted above they should read the link from oldhoopster that proves just how wrong and irresponsible the other post was

 

Doug has also eaten Tide Pods with no ill effects, so go figure!!!

Really, Doug??? Tide Pods??? It's a stupid phenomenon!!! You shouldn't do this!

 

I've worked with acetone in labs for years, mostly used for drying glassware, but other uses too. Main concern is that it is highly flammable, and in certain proportions, its vapor can form explosive mixtures with air. Toxicity from brief exposures is not a big concern. I don't recommend direct skin contact. If run over skin it can be absorbed, and it will partially de-fat the skin, leaving it dry and irritated. Breathing incidental vapors over a short period of time is not a concern, but could be harmful if prolonged (hours). Deliberately inhaling the vapor should not be done. If you detect a strong smell of it while working with it for more than a few minutes, ventilation is not adequate or too much of it is being allowed to evaporate. If there is a continuous strong smell, there is a significant risk of fire or explosion from spark or flame.

Acetone is produced in the body, usually in small quantities from the metabolism of fat. However, in some diseases, like diabetes, it can be produced in large quantities. One of the signs of diabetic ketosis and coma is an acetone smell of the breath of the affected person or animal.

Although environmental authorities will state that waste acetone should be taken to a waste disposal facility, small amounts can be poured down the drain with lots of accompanying water. Acetone will attack many plastics unless it's diluted with lots of water, so keep that in mind with regard to storage, use and disposal. Acetone is miscible with water in all proportions, so easily diluted to the point of being of little toxic or flammable risk.

Do not attempt to distill acetone to purify it for re-use. There is a significant risk of fire or explosion if not done right.

Cal

 

"BadThad, posted: "And don't forget the flowlines, they are like little razors on a microscale and are damaged VERY easily."

I admire your knowledge as a chemist but to post that cotton HAS ANY EFFECT on a coins flow lines is well...

"Microscale?" I don't think 1/6000+ collectors even examine coins on a micro level. As for damage, we may find some hairlines across a flow line under magnification and if we wish to rub on a coin w/cotton for fifteen minutes we may shine the metal flow up enough to know something unusual happened.


GDJMSP, posted: "Believe what ya want, pretty much every painter there is on the planet uses acetone on a daily basis and gets it all over themselves - with no harm done."

I disagree, for whatever the reason (genes?) some folks may not be as affected as others. That said, I can count over two dozen old friends and relatives who blame chemicals such as acetone for their problems.

Perhaps it's like Agent Orange. It does no damage until it does but who knew. Lucky this is a "free" country and we can play with chemicals. I've been playing with acetone improperly for half a century. I'm waiting for the hammer to fall.