PVC damage on silver coins

Discussion in 'Ancient Coins' started by ambr0zie, Feb 28, 2021.

  1. ambr0zie

    ambr0zie Dacian Taraboste

    Hello ladies and gentlemen,
    I have 2 coins, from different auctions, but most likely from the same source (I have seen many coins with the same issue in the same auctions)
    upload_2021-3-1_0-44-27.png
    I got this coin because I liked the reverse, but as you can see, on the obverse the damage is quite extensive.
    The previous coin I got has the same problem (and also Julia Maesa, apparently she hates PVC). I soaked the old one in acetone - but not pure acetone as I don't have it, I need to buy some soon - but the effect was unnoticeable. I dipped it with a Q-tip and either I'm paranoid or some portions started to shine, unnaturally, so I just left it alone.

    Without the damage, this coin, and the other one, would have been quite attractive coins ...

    Do you think I should try something on this one or not? I am not bothered by the green spots and not very bothered about the damage itself, my only concern is if the coin will continue degrading.
     
    galba68 and Bing like this.
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  3. robinjojo

    robinjojo Supporter! Supporter

    You should buy some pure acetone. The diluted acetone is not very effective, as you noted. The 100% acetone makes a world of difference.

    Now you mentioned that soaking the coin had no effect on the obverse. Judging from the photos the obverse might have deposits of oxides and not PVC deposits. Acetone has no effect on oxides.

    I just opened the image in Photoshop and enlarged it. It really does look like oxide buildup.

    So, I would suggest that you try soaking the coin in 100% acetone. The acetone will not affect the metal. If the deposit persists, try soaking the coin in distilled water for several hours or overnight, and see if any of the deposit can be dislodged with a toothpick.

    You might be able to remove some, but not all of the deposits. At this point I would leave the coin alone and let it tone. Once the bright areas start to darken naturally, over time, the coin will look better.

    The reason I suggest not to go further is that complete removal of the deposit might reveal a rough or corroded surface, or it might reveal a smooth surface - that's something of a gamble - you never know what lays beneath.
     
  4. ambr0zie

    ambr0zie Dacian Taraboste

    Thank you. I will buy some pure acetone as I know it doesn't affect coins.
    I am not sure if it's oxide - I soaked the previous coin, not this one (currently waiting for the coin in the thread to arrive)
    upload_2021-3-1_1-26-23.png
    They are very similar in condition (minimal circulation wear, but...) - I am 100% sure they belonged to the same person and I saw at lest 30 similarly damaged coins in 2 auctions.

    As you can see, in both examples, the damage affected the surface. Coin 1 obverse legend IVLIA MAESA A[vg] - VG gone.
    Coin 2 legend IVLIA MAES[A A]VG - AA gone.
    I checked the coin from this message, the letters are simplu "polished"
    I am not bothered too much - the problems reflected in the price, my only problem is making sure the damage doesn't evolve.
     
    Bing and robinjojo like this.
  5. robinjojo

    robinjojo Supporter! Supporter

    My experience is that silver is much more stable than, say, bronze. Unless the silver has a high copper content, there shouldn't be any progressive corrosion, unlike bronze, where bronze disease can develop, especially in humid conditions over a period of exposure.

    The silver will darken over time, and that's a good thing, especially for an ancient coin.
     
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