Acetone

I may be wrong but I've never seen fingernail polish remover that is pure Acetone. The reason is women use it to remove fingernail polish. Other ingrediants have been added for a decent odor, softeners, etc. Every bottle of fingernail polish I've ever seen contains way to much STUFF to consider using on coins.

Correct, Carl. Most nail polish remover has much MORE than acetone in it!

I had an 1863 Indian cent in my 7070 Type Set album that was COVERED in verdigris. I decided to test the suggested solutions and grabbed my bottle of acetone (NOT nail polish remover. Goof Off! seems fairly pure). The suggestion I read said to try distilled water first, then acetone. I didn't have any distilled water, but I had some bottled water which seemed to be more reasonable than tap water (I'm not sure why that made sense at the time. That might have been the beer talking). I poured a bit into a cup over the coin and left it for about half an hour. I was not surprised that it had no effect, so I pulled it out of the cup and dabbed it off with a lint-free cloth so I could move on to acetone. I was surprised to see patches of green on the cloth, so I dabbed the coin some more. With a VERY gentle rub I was able to remove ALL of the verdigris from the coin. Don't underestimate the ability of a soak in water to solve the problem, but next time I will buy some distilled water (or capture some rain water) to minimize contaminates.

I thought nitrates were mostly due to runoff (via fertilizers) and more likely to be in the local water supply than in the rainwater. Sulfides are indeed a problem in some areas, but I live in the boonies where land based pollution (nitrates) are more of a problem than acid rain pollutants (sulfides).

Regardless, a 30 minute soak in tap water, rain water or bottled water would seem to be better than acetone for a first step. Distilled water would be best if treating lots of coins, but to try it out on one coin to see, any reasonable drinkable water source would be a good test. I would argue that tap water (with flourides) and bottled water (with flavor enhancers) are certainly no better than rain water. I used Deer Park Natural Spring water which claims to be 100% pure spring water, but springs, by definition, have mineral deposits that would likely play a role.

Agreed, distilled water would be best. If I ever need to remove verdigris again, I will buy some distilled water. I was sure it wouldn't do any good and was ready to move on to acetone, so I just used some bottled water I had handy that was at room temperature. I was very pleasantly surprised by how a 30 minute soak in just water with a gentle rub of a lint-free cloth did the trick!

You can just boil water to see the reside. You can also create your own distilled water on the stove if you wish. I was cleaning a lower grade coin that had endured many hardships so I didn't bother distilling the bottled water I used. If I were going to do it again then I would make or buy distilled water.

Depends. If a recent print, Acetone should remove it and no problem. IF, it's been there for a long time may be to late.

If the print has been there for a while and won't come off with acetone (and sometimes acetone can't get recent prints off either) a dip may work on it.

If that fingerprint is more than 4 days old, it's there for good.

"Dipping" a coin describes stripping the surfaces with thiourea, an acid which attacks silver. In numismatics it's best-known under the brand name "E-Zest." The use of that substance counts as one of the harshest of cleaning methods and the easiest way to completely screw up a coin short of a wire brush; although there are very narrow conditions under which this treatment might be recommended, it is not for the faint of heart or anyone but a collector extremely experienced in its' proper application. Fingerprint or not, I would not bring that coin within half a mile of thiourea.