Purple Or Milky Discoloration On Proof Silver Eagles

[Beijim]

Hi!

 

I have several proof American Silver Eagle coins I wanted to submit to NGC for grading. Upon close inspection, however, I discovered that the coins suffer from varying degrees of purple splotching, primarily on the mirror fields. Usually the discoloration appears to have begun at the coin's edge, progressing inward. In addition, a couple of the coins exhibit small milky spots.

 

On some coins the discoloration is easily eye visible; on others the problem is obvious only under magnification. I'd like to submit the coins for conservation, but only if you feel it's worth my while to do so. The purple "toning" seems a common problem among proof Silver Eagles - is this something that conservation can remove and neutralize? A related question (because I'm curious) would be what causes this particular type of discoloration - i.e. does it derive from specific chemistry in the purple velvet cases in which the Mint used to ship these coins?

 

Since I'm looking for PF69 UC grades on these coins (the surfaces are quite nice except for the discoloration), the question in my mind is whether the act of conservation will itself compromise the mirror fields to a point at which grading PF69 UC or higher would be improbable.

 

Thanks very much for your assistance!

 

[NCSSilliman-migration]

We receive a lot of coins with this type of problem. It is mostly like a combination of mint handling and packaging.

Most of the time this type of residue is fairly easy to remove. We have however seen a few instances where the residue is removed by light stains remain.

 

There are several types of "milky" spots. One is very light...more of an outline of a spot and is caused by fluid drying on the coin. This can usually be removed with out difficulties. The other spot is a small solid white spot. It almost looks like a dot of paint in some cases. We are not entirely sure what causes these but rarely is ever come off.

 

We get a huge number of modern coins submitted to us with the problems you described. With the exception of the solid white "milk" spots all of these problems are conservable and the coins look great when finished. Nothing in the procedures we under take will damage the coin or affect the cameos or fields negatively.