Is it normal for proof coins to still be covered in grease?

I have a commemorative coin from a proof set that still has lots of blue/gray grease on it. All around the edges & splotches of it on the reverse field. Is this a common occurrence even in proofs?

 

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Obviously not. If you read about the minting process for proofs, you see that the planchets are washed and dried before striking, but not after. Lubricating the presses is a routine operation, but the working parts -- the moving parts -- are the only surfaces that need it. Dripping down into the dies is a quality control problem.

I take it that you purchased the coin second-hand, in the aftermarket, rather than directly from the Mint. There is not much you can do, except return it to wherever you bought it. I hesitate to recommend any method for cleaning the coin. A common degreaser like alcohol, acetone (nail polish remover), xylene or even gasoline would do the work, of course, but the surface of the coin might be ruined and I have no experience on which to base any opinion. I'm just cautioning you that there may be no way to fix the problem except to return the coin.

 

Proof coins tend to haze over time... it sometimes has a blueish look to it. I recommend a 5-10minute soak in pure acetone and then a wash in distilled water and pat them dry (don't rub). This has worked on some haze for me in the past.

 

I respect your authori-tah!

Not owning a store, I clearly have not seen enough proofs. Thanks for the information.

 

Here are pics of the grease in question. The splotches are all over it and fairly thick in some places. Thanks for the advice on how to get rid of it.

 

Never EVER use nail polish remover.
It has other impurities in it that may attach to a coin.
Nail polish remover is generally 40% acetone, anyway.
Pure acetone is an option, but really shouldn't be used by people not familiar with it.

 

If you touch the coin on the edge,not the face, is the material like grease? or it is hard like plastic? Your last photos do not look like haze to me, but more like something someone applied to help "protect" the surface. The photo of the lettering looks similar to shellac or acrylic, which acetone doesn't remove.

 

You sure about that ?
I've seen 100% pure acetone eat through paint and fiberglass resin on a Corvette.

*edit*
Mind you, it was soaked into a sponge and sat in one spot of the vehicle.

 

Thanks desertgem. Truthfully, I've been afraid of pulling it out or handling it. Ironically, it isn't even a valuable coin per se, but it's a proof and so pretty except for that grease! I would hate to be the one to scratch it up!

 

Are you sure that it isn't pieces of plastic scrap from the holder itself? It is suspiciously like the color of the surrounding plastic...

 

No, it's not the plastic. I think desertgem was correct and that someone applied something to it. I purchased these 2nd hand and the container had previously been opened. Live and learn I guess.