Artificial Aging

I could conceive of that, or a couple of other equally-greasy motives, depending on the original seller. Depending on the auction, blame could also lie with the auctioneer, since it'd be tough to package a coin in storage or regular ownership with a finish like that.

Obviously, the stuff has to go away before you can form an intelligent opinion of the quality of the coin you bought. Do a Forum Search for "acetone," learn the proper usage which we've discussed many times here, and have a go at the coin with it. That should suffice, and then you can see exactly what you actually received.

There is a product on the market for darkening copper coins called "Dellers Darkener" it leaves the coin a bit oily, it works okay, I don't use it myself though, as I don't alter coins I own or sell, though I've tried it, it looks a bit like vaseline, defintely contains some sort of petroluem products I'm guessing. Never tried it on silver but it sounds kind of like what the OP is describing.

http://www.wizardcoinsupply.com/del...arkener.html
Olive oil will remove it completely, so they say.

An acetone soak should remove what ever you have on your coin without any damage at all.

What does the coin smell like? That is a good test to start with.

Nail polish remover and Acetone are NOT the same thing, do not use them interchangeably. Some nail polish removers may contain acetone but it will also contain alot of other things you do not want on your coin(dyes, fragrances, nail conditioners, etc).

I hate to add this note - but I know for a fact the Chinese fakers were somehow coloring their coins darker to make them look more authentic. I know b/c I deliberately got some fakes to learn about them. The dark coloring came off easily like you said.

can you post some close-up pics? What kind of holder was it in? If it was slabbed, couldn't the number be traced? There is info posted on some of the grading co.'s that tell how to recognize a fake slab.

What year/mm is it? I have pics form the website that used to list the main counterfeiter's stuff and can probably post a pic here so you could compare them.

Let me know the date and I can get the pic of the fake for you - I am not sure if it will help or not - but it will be a start

No problem on the picture. Now that I know yours is an 1877-this is good news. Because I looked through the list of pictures and inventory this guy made/makes and there is no 1877. Here is a total list of what he does make:
Replica Seated Liberty Half-dollar Replicas
1861 Confederate Half-dollar
1850 P, O
1851 P, O
1852 P, O
1853 O
1866 P, S
1870 S, CC
1871 S, CC
1872 P, S, CC
1873 P, S, CC (for some reason he had these listed twice if they were like his other listings it was because he was offering an uncirculated version also)
1874 P, S, CC (also listed twice)
1878 P, S, CC
1879 through 1890 P mint only.

And for the fun of it here is a picture of one of his fake Seated halves he sells:



I can almost guarantee if this replica coin was in hand and you rub it with a white cloth the results would be the same as you found with yours. The few fakes I got from him that looked like this were covered with this substance (whatever it is) and could be wiped clean.

He was the major seller on ebay of replica coins who used to have pages and pages of copies for auction from all different countries-until ebay kicked them off. His was the company that was featured in many articles across the web concerning Chinese replica coins. Since his inventory does not carry one of your date, it made me feel a bit better about your coin. I am not saying this guy is the only counterfeiter out there, but he was/is the largest.