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

Discussion in 'Coin Chat' started by mpcusa, Feb 13, 2022.

  1. mpcusa

    mpcusa "Official C.T. TROLL SWEEPER"

    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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  3. mpcusa

    mpcusa "Official C.T. TROLL SWEEPER"

  4. Bambam8778

    Bambam8778 Well-Known Member

    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.
     
  5. mpcusa

    mpcusa "Official C.T. TROLL SWEEPER"

    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
     
    Cheech9712 likes this.
  6. Casman

    Casman Well-Known Member

    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.
     
    alurid likes this.
  7. mpcusa

    mpcusa "Official C.T. TROLL SWEEPER"

  8. mpcusa

    mpcusa "Official C.T. TROLL SWEEPER"

    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 ?
     
  9. Casman

    Casman Well-Known Member

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

    Pickin and Grinin Well-Known Member

    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.
     
  11. Insider

    Insider Talent on loan from...

    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.
     
    Cheech9712, John Burgess and mpcusa like this.
  12. Pickin and Grinin

    Pickin and Grinin Well-Known Member

    Thats the first I have ever heard that, it's a valid thought, I see a lot of these raw.
     
    Cheech9712, mpcusa and Tater like this.
  13. Insider

    Insider Talent on loan from...

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

    mpcusa "Official C.T. TROLL SWEEPER"

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

    Insider Talent on loan from...

    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.
     
    MIGuy, Cheech9712 and Revello like this.
  16. GDJMSP

    GDJMSP Numismatist Moderator

    There have been quite a few theories about what causes milk spots, but that's all they are - theories. The truth is no one actually knows what causes milk spots, least of all the mint, or any mint, because not a single one of them has ever been able to prevent them from developing on some coins.

    And of thinks about these theories for a just a minute it soon becomes obvious that none of the theories about how and why milk spots from are or even can accurate. The reason for this is simplicity itself. The reason is if it was something, or anything, that "got on the coin", whatever that something was could be easily removed without harming the coin !

    But to this day no one has ever been able to find any method of removing milk spots without permanently harming, damaging, the coin. Therefore the spots cannot be "on" the coin, they have to be "in" the coin. In other words, physically within the metal itself - and thus incapable of being removed without permanently damaging the coin.

    This pretty much leads us to only one likely theory, that the milk spots are caused by some sort of impurity within the molten metal when the alloy is mixed. And, that milk spots only show up on those coins when that impurity, by pure chance, happens to end up close enough to the surface of the coin for it/them (the spots) to become visible after a given amount of time.
     
  17. charley

    charley Well-Known Member

    Sigh.....
     
    Insider likes this.
  18. Mr.Q

    Mr.Q Well-Known Member

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

    mpcusa "Official C.T. TROLL SWEEPER"

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

    Casman Well-Known Member

    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.
     
    Cheech9712 likes this.
  21. mpcusa

    mpcusa "Official C.T. TROLL SWEEPER"

    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 :)
     
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