Tell me about milk spots.......

I am a little confused, more of a currency guy then a coin one but was looking
at this particular coin, so were the spots there before the grading ? obviously
worth less as the same coin is selling for a hundred dollars more, what causes
them ??

 

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To my understanding, the milk spots come from the solution that the mint washes the coins in. The newer coins are plagued with them. I'm sure others will have a more scientific, detailed explanation.

 

Thanks for the info, I think that part make sense, but the question is di it turns out that way in the slab. or graded that way, just bought this one, so kind of the question will mine eventually get the measles...LOL

 

Spots not there when graded and occur after at any point from days to years later. Some claim an acetone bath prior can prevent them from forming. If I recall correctly there was a post somewhere that there’s a process to remove. It could have been tarnx. I avoid the issue by not collecting that stuff.

 

So does this mean its a common problem for all alike coins and would tha be just a silver problem or a GOLD one to ?

 

Silver only proof and Unc. Only prob with the Gold is the red dot spots.

 

Gold is nearly impervious to contaminants.
I have seen copper spots on gold but don't think I have seen milk spots on much gold if any.

 

Some believe they can occur when the compressed air is blown onto the coin before slabbing. That may be the case her because that coin would not have been graded 70.

 

Thats the first I have ever heard that, it's a valid thought, I see a lot of these raw.

 

Turn on one of these, even with a filter and until the line is cleared it looks like smoke blowing out of the nozzle.

 

Some kind of reaction I guess, but if they think compressed air is the problem then why do it ?

 

There is a difference between "milk spots" (white areas and spots found on silver coins from the mint) and other spots that come in different colors including white. I THINK that many of the small spots that develop on slabbed coins come from the air compressors at the TPGS.

Air is less damaging than a brush to remove dust and other contamination.

 

Sigh.....

 

Interesting post and theories. Learn something every day thank you.

 

Thanks for your insight Doug, as always
very much appreciated.

 

If the impurity was in the coin, then a preventative acetone bath would be ineffective. I’ve heard that if given an acetone bath prior to submission or storage raw that the milk spots do not develop. Is this true, I don’t know as I dumped all my ASE’s and no longer collect them.

 

I think if it was a major problem they
would get to the root cause pretty
quickly and fix it, theory’s are nice
but actually know the reason is better