Sometimes I pick up a coin, that I have just bought from EBay, and it feels oily. Has the coin been oiled? If it has been oiled, what should I do about it?
Are you holding it by the edge's, i don't know what could cause it, but pat (not rub) with a microfiber.
I hold it by the edges. Mostly, I find copper coins that feel oily. After reading about Coin Care, I wonder if this has been used on the coin.
I'd guess it's olive oil. It can be hard to get off. Detergents are probably the way to go. Don't do anything to unc coins; send them back.
The oil could be anything, any kind of oil. Products like Coin Care and Blue Ribbon are oils and a lot of people use them on their coins. Some people use mineral oil, even vegetable oil, thinking it will protect their coins. Anyway, to get the stuff off use xylene, not acetone. Acetone doesn't work very well on oils. Use the same procedure that you use with acetone (but use xylene) I have described many times before, found here - http://www.cointalk.com/t193708/
They may have been retoned/darkened with something like a product called Deller's Darkener. This is a mixture of vaseline and sulfer powder that may leave an oily residue. Gasoline will remove it. A lot of cleaned copper coins are being doctored in this way and put up for sale on eBay.
Thanks for the advice. I suspected it was not the best thing to have on coins. I have always tried to clean it off, but found before that acetone is very tricky to use on copper or bronze. I have bought some xylene to use instead.
Huh? As a casual reminder, coins are made of metal and machine oil is used in the minting process. Think "grease filled". I bought a sealed bag of Eisenhower Dollars hoping to find some MS66/67 coins or at the very minimum some cool errors. When I opened the bag, a good portion of the coins looked as if they'd been swept off a greasy garage floor. The black, thick, metal laden grase was visible to the naked eye. The inside of the bag looked as if used transmission parts had been stored in it. Machine oil is supposed to be rinsed or cleaned (yes, the US Mint cleans coins) off the product before they get shipped out but this does not always occur on a 100% effective basis. Think "rinse spots" on Zincolns.
I've found the same black stuff in the bags of cents I bought. Most look like pieces of black crayon.
The coins I am talking about are mainly ones about 200 years old if not more. Rather this is oil applied well after the minting process.
My "Huh?" is aimed at the comment "might be PVC oil from PVC cardboard coin holders." I've never heard of a PVC cardboard coin holder and assumed you were referring to cardboard 2x2's. Cardboard 2x2's use a non-PVC Mylar film to protect the coins. Exactly what were you referring to?
You are correct. Olive Oil is used on old copper coins as a cleaning meduim as given a long enough soak, grime picked up from circulation can easily be removed. Typically, these coin take on a dark color and the practice is widely used and accepted by Old Copper Collectors. Old meaning old coins and not necessarily the collectors.
PVC cardboard 2x2's exist (might not be made anymore). Bought a coin not too long ago that had an oily residue from the 2x2 it was in :\
Not exactly. The mint does not do any cleaning after the coins are struck. The only cleaning done by the mint is to planchets.
