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Milk Spots on Proof Lunar kilo coin....

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I just purchased a proof lunar kilo coin graded PF69 Ultra Cameo. Unfortunately, it has a few milk spots on both sides. My question is, what do you guys think I should do with it? I called NGC and they told me to send it in for an "Appearance Review". Now, if they are able to successfully remove the spots, will they ever come back? I heard once a coin is infected its essentially uncurable. Should I return it or give NGC a crack at it? It's a beautiful coin and I really want to keep it but theres no way I can tolerate the milk spots on it. Thanks for any responses.

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Milk spots on proof coins are very hard to remove successfully. Often upon curation, even whe expertly done, there is residual left and a "rim" of the original spot is left on the coin surface and the surface that was beneath the spot is left imperfect, particularly if on the mirror surface. These spots are actually from the wash that is used in producing the proof planchet. Thus, when the coin is struck, the spot becomes part of the surface of the coin and not just a layer "on top" of the surface. You would be better off returning the coin for a refund. If you can't then you can send it in for appearance review and see what NGC/NCS does or suggests.


There's debate over whether milk spots actually affect the technical grade of a coin. Since they are part of the coin "as struck," some consider them to be nothing but cosmetic and therefore do not affect the technical grade of the coin. Others argue that eye appeal affects numerical grade (while others disagree). Still others argue that milk spots affect the surface of the coin and are therefore part of the technical grade. So, you'll have to take your pick, but regardless, if you can't live with them, then you should seek another coin.



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NCS does a pretty good job of cleaning up some types of surface issues. As hoot said above, the white spots of death are pretty difficult to deal with, but all is not lost. Here's a rare panda coin that got a PF68 grade after NCS removed some of the white spotting:




You can see in the close up photo that some of the spot still remained, but it's much harder to see. The spots are now only visible when the coin is tilted at the right angle to reveal the rougher surface texture where the spot used to be.


As far as the white spots being an "infection", I don't know. It doesn't sound like it to me though, from what hoot said. Silver is fairly resistant to corrosion, and there's not many things that can "infect" it, unlike copper. In copper, it's chlorine "bronze disease" that "infects" the coin. If you can get all the chlorine off the coin, the disease can be stopped.


Whatever these white spots are, they clearly aren't possible to completely remove. However, I haven't seen anything yet that leads me to believe that they're somehow growing like bronze disease does. When I see them, they're always discrete white spots, and never large patches of area. If it were growing, the spots would eventually all merge together until they covered the entire coin. Since I haven't seen anything even close to that yet on coins that are 20 to 30 years old, I don't think it's going to happen.


I think you should ALWAYS buy coins that have been conserved by NCS, just in case though. PVC in the original package DOES contain chlorine, and while it doesn't produce any sort of disease effect like it does on copper, it will continue to eat into the silver until the coin gets properly conserved. So, in short, if your coin hasn't been conserved yet, you better get it done.

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