US Mint Silver Proof Set Yellowing Issues

Discussion in 'US Coins Forum' started by Chris Winkler, Dec 11, 2020.


    GDJMSP Numismatist Moderator

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  3. Chris Winkler

    Chris Winkler Well-Known Member

  4. Collecting Nut

    Collecting Nut Borderline Hoarder

    Any type of glue gives off gas that hurts the metal. It also damages the packaging and that's not good either. The yellow is toning and that is caused by how and where they are being stored.
  5. charlietig

    charlietig Well-Known Member

    I have come across nicotine film before, that really seems to yellow the plastic and haze the coins.
    Paul M. likes this.
  6. thomas mozzillo

    thomas mozzillo Well-Known Member

    If I used the word recharged it was the wrong word. The crystals in the package are dark blue. After they start turning a pinkish color, it means they've absorbed enough moisture. You then put them in an oven at 300-350 degrees for a few hours until the crystals are blue again (I guess you could say that's recharging them). Instructions are on the package.
    In addition to the site given by @GDJMSP, 2 other supply sites are: and
    Chris Winkler likes this.
  7. Paul M.

    Paul M. Well-Known Member

    I beg to differ. It is most certainly possible to stop toning entirely. The issue is that nobody is really going to go to the trouble to do it due to the utter impracticality of it.

    What you'd have to do is store the coins in a hermetically sealed box under a dry nitrogen atmosphere. You can't store them in a safe, or exposed to open air, or even vacuum sealed inside plastic bags and hope to stop toning. You have to keep the stuff that causes toning out entirely, and that's pretty much the atmosphere.

    Nitrogen isn't completely inert, but there are no direct reactions between silver, copper, or gold and nitrogen gas that will happen at anything close to room temperature. We're talking well over 1500 degrees C before anything fun happens, and, by that time, your coins are melted anyway.

    While I've never heard of it, it's not entirely crazy that, say, a museum might store certain items under dry nitrogen like this. Original copies of the Declaration of Independence, Articles of Confederation, and the Constitution are stored at Independence Hall, under argon in a precisely climate controlled environment, including sufficient humidity to keep the paper from cracking.

    I suppose you could object that this doesn't really stop toning entirely, but, with proper maintenance of the system, I see no literal reason why you couldn't keep copper mint red for thousands of years under these conditions. That, to me, effectively amounts to stopping the toning process.
    Spark1951 likes this.

    GDJMSP Numismatist Moderator

    There is an easier way, you can use sealable glass canning jars similar to these -


    No, you don't fill them with nitrogen or other inert gas, but they are truly airtight and will last for years. But eventually you have to replace the seals with new ones. And what little air is inside the jars with the coins, well, it isn't gonna do much because there isn't enough of it.

    And as with your method, it really isn't practical for a lot of folks, but it will and does work.
    BJBII and Chris Winkler like this.
  9. John Burgess

    John Burgess Well-Known Member

    Well, couldn't you buy mylar bags and then vacuum seal the coins for eternity or as long as the seal holds?

    For sure under a vacuum there shouldn't be any oxidization or moisture of any kind.

    Still a step too far for me to want to make, and so is the glass jars, or the argon or nitrogen gas or swapping out silica packets regularly...
  10. GDJMSP

    GDJMSP Numismatist Moderator

    Yeah, they'll work as they are not air permeable like plastics are. But they are also not transparent and if any moisture ever did get in, the aluminum could and would cause an unfavorable reaction with the coins if it came into contact with the coins.

    But as long as the coins were in inert hard plastic coin holders, that couldn't happen.
  11. STU

    STU Active Member

    i use the silca packs that come in just about everything you buy they are cheap and work very well i hve sets that go to the 40s up to todays and never had a problem with yellowing they look like the day i got them
    Chris Winkler likes this.
  12. Cheech9712

    Cheech9712 Every thing is a guess

    Can we see a few of your 30’s proof sets. We only have sets from the 40’s. Think those are the first coins my ma bought back then. Well could of been dad also
  13. Cheech9712

    Cheech9712 Every thing is a guess

    Thanks cuz I got early mint set never opened. Was wondering. Yeah
  14. yakpoo

    yakpoo Member

    I have the 1938-1942 sets in their original boxes. I wrap the coins in aluminum foil to prevent any reactive chemicals from reaching the coins. I've been on the lookout for the 1936 and 1937, but the ones I've seen have sold for more than I was willing to spend.
  15. Kentucky

    Kentucky Supporter! Supporter

    ...or you could store them in a Helman's Mayonaise jar on Funk and Wagnal's porch.
    PDKHort, CoinCorgi and green18 like this.
  16. thomas mozzillo

    thomas mozzillo Well-Known Member

    I can just picture it. Coins in inert plastic holders, placed, along with a dehumidifer, in a sealed mylar package, packed in a PVC free plastic box, stored if a safe deposit box, etc. LOL :)
    John Burgess and Chris Winkler like this.
  17. All my Limited silver sets,2012,2013,EG,Have developed the yellow toning issues,While the later sets,2016 EG, where the coins are in individual capsules have not.The sets were stored under the same conditions so I would place the blame on the inserts the coins were placed in containing sulfur or some other chemical.
    Chris Winkler likes this.
  18. Chris Winkler

    Chris Winkler Well-Known Member

    The pic i posted is a set from 2014 i saw for sale that appears to be in capsules, as is the 2016 i just picked up. With the printed insert technically not touching the capsule, though i can see over time any sulfur in the cardboard can release & absorb through the capsules. Though it does have some sort of plastic sheet over all the coins that my 2016 does not have.

    A question is how can a desicant that is designed to absorb mositure absorb sulfur if it indeed works on coins?

    Now the BIGGER question is can cardboard be made w/o sulfur??? This goes back in time, especiall Morgans with edge toning from sitting in display books.
  19. GDJMSP

    GDJMSP Numismatist Moderator

    I envy you. I spent 40 years looking for them and never found any. Well, I did find 1 towards the end of my collecting US coins, a '41 set, but at the time I didn't have the cash to afford it.
  20. thomas mozzillo

    thomas mozzillo Well-Known Member

    I don't think we can answer all your questions. I'm not telling you this in a mean spirited way but to help you. You need to start doing some research. You can start by checking out the websites shown here:
  21. thomas mozzillo

    thomas mozzillo Well-Known Member

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