cleaning varnish off an old copper coin

Discussion in 'Coin Chat' started by Southernman189, Sep 17, 2021.

  1. Southernman189

    Southernman189 Well-Known Member

    I still say, if you don't know ASK!! Well I am asking. A month or so ago there was a chat about acetone dips (I never heard of such but was intrigued) now the question is, does dipping work on copper and would it remove I am guessing varnish partial coating. OR if when the varnish is removed would the coin look like a spotted Giraffe removing the varnish and leaving the uncoated spots alone. Here is the coin with the varnish (or whatever the coating is) WIN_20210917_21_57_43_Pro.jpg
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  3. desertgem

    desertgem MODERATOR Senior Errer Collecktor Moderator

    If I don't know for sure what kind of varnish it is , I start with water, 90-100 ethanol, acetone, xylene ( sometimes not due to difficulty to obtain~ unless you are a college chemist), mineral spirits, separately in that order. If it stays the same , it may be epoxy, acrylic, alkyd, or polyurethane and you would have to use more hazardous or likely to damage . Is it colored or relatively clear? IMO, Jim
    Mr.Q, Southernman189 and Oldhoopster like this.

    GDJMSP Numismatist Moderator

    When talking about coins the word dip or dipping has a very specific and limited meaning, it refers to using a commercial coin dip, all of which contain an acid.

    When talking about using distilled water, acetone, or xylene, rinsing would be the proper term to use.

    As for your basic question, will acetone or xylene remove varnish from a coin ? Yes, they will. But since there are several different kinds of varnish with each being made of different things, some can be removed with acetone while others will require using xylene to remove them. And no, there's no way to determine which to use except by trial and error. First use one and if that works fine, but if it doesn't then use the other.

    But as desertgem said, there's no guarantee that what's on the coin is varnish at all, it could easily be almost anything else. So acetone or xylene may or may not remove it if it is something else.

    Yes, what you're describing could very easily happen. The reason it could happen is because the varnish (or coating) would have been stopping toning from occurring in the covered areas. But all the while allowing toning to occur in the uncovered areas. And since neither acetone nor xylene will remove toning, once the the varnish or coating is removed it will reveal untoned metal that will be a different color than the metal that is toned because it was not covered. And that will result in pretty much the look you're describing - the coin will look to be spotted with different colors.

    Many decades ago varnish and lacquer were used by many collectors in an effort to protect, primarily copper coins because copper is so reactive and tones so easily but some also used it on other coins as well, coins from toning. They thought it was a great idea at first and it seemed to work. But they failed to take the long term effects into account. With time, the varnish changed colors and became ugly, and some would flake off here and there. Or, any contact with other surfaces could and would wear the varnish off, again making it look ugly. And so eventually they learned from their mistake and stopped using the process. But every now and then coins with varnish and or lacquer on them still show up, and questions just like yours are asked.
  5. Southernman189

    Southernman189 Well-Known Member

    sounds like "leave it to hell alone"
  6. John Burgess

    John Burgess Well-Known Member

    Better pictures of the whole coin might help in determining what it is. This picture kind of looks like the coin is worn, and the coating you have issue with is cracked and old and chipping off here and there. If it's old, it's likely laquer. But the metal under what's left has been protected while where its come off has toned so even when you remove it, it's going to look "off" from the metal not toning where it's protected, and toning where it isn't protected, but if the laquer is old and cloudy/ crusty looking it might still be an improvement.

    It could probably be removed with pure acetone if it's laquer and pure acetone should not damage the coin itself. Probably an hour soak, then a quick rinse in clean acetone to wash off any remaining dissolved laquer.
  7. Southernman189

    Southernman189 Well-Known Member

    ok here is pictures of the whole coin front and back varnish (or whatever) is around the words mostly both sides. 1838 Slave Girl Obv..jpg 1838 slave girl rev..jpg
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  8. cplradar

    cplradar Talmud Chuchum

  9. cplradar

    cplradar Talmud Chuchum

  10. Mountain Man

    Mountain Man Supporter! Supporter

    Asked and answered above, but please do post your results for the rest of us to learn from. Good luck.
  11. Mr.Q

    Mr.Q Well-Known Member

    I never use any chemical on my coins. What the CT'ers are say is absolutely correct. Good luck!
  12. Collecting Nut

    Collecting Nut Borderline Hoarder

    Best wishes in whatever you decide to do as it’s a nice looking anti-slave token.
  13. Randy Abercrombie

    Randy Abercrombie Supporter! Supporter

    Over the years varnish has had a number of different solvents. Older varnishes were most typically cut with alcohol. Put a drop or two of denatured alcohol and see if that will soften the varnish. I don’t think denatured alcohol would react at all with your coin.
    -jeffB and John Burgess like this.
  14. JimsOkay

    JimsOkay Active Member

    That’s a great coin, be careful.
  15. John Burgess

    John Burgess Well-Known Member

    My opinion seeing the whole token is to not mess with it. I think when you do get it to base metal and remove the coating it's going to be different colors where its been protected.
    I do believe it's seen some wear and I'd just suggest maybe carrying it as a pocket piece just for a little bit get some hand oil into the coating and put some life back into it from some light handling.. maybe flake off a little more and see what the color is under those areas before going further, but don't rush it and if the flaking off of the coating is making things worse then just stop.
    Theres a slight possibility It's just really old mineral oil or olive oil, layered on over and over, I don't think so but that possibility exists, and it's just built up into almost a plastic coating over the years. If this is the case the color underneath won't be too much different as it would of likely turned color before the treatments were applied.

    Really nice piece. I'd just take my time on it. Laquer or varnish or just coated in old dried oil, take your time and see how it goes, and then determine what to do. Any of these options aren't reactive and doing nothing won't hurt it either, it's just not pretty.
    Trying to correct it before you're sure what it is and what's underneath could make it even worse, not necessarily damaged, but just less eye appealing.
  16. cplradar

    cplradar Talmud Chuchum

    It gets worst with age though.
  17. tibor

    tibor Well-Known Member

    You might reach out to the "Early American Coppers" club for
    some advice. Many knowledgeable collectors there.
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  18. 1865King

    1865King Well-Known Member

    I had varnish on a 1798 large cent. It was an extra fine coin. I was able to remove the varnish but, once removed it exposed the fact the cent was cleaned before the varnish was applied. Because it must have been done a long time ago the varnish became dark with age. I didn't realize what the condition was until the varnish was removed.
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  19. tibor

    tibor Well-Known Member

  20. GDJMSP

    GDJMSP Numismatist Moderator

    I never said that. Personally, I'd remove it because things will only get worse. But you needed to know what you'd end up with if you did which is why I explained what I did.
  21. ldhair

    ldhair Clean Supporter

    I would try to help the coin as well. Water first, acetone next and xylene last. That's were I stop and I never rub the coin. Just a bath in each solution. I let a coin soak for a few hours. Watch the color of the solution. It may tell you if the solution is working.

    One other thing that may help is to use a toothpick. Again no rubbing. Just press on a thick spot in the coating to see if the bath made it soft. If you see color change to the solution or the coating is turning soft, stay with that solution for another bath or two.

    I know that some folks use olive oil but I never went that direction. Never had a lesson on using it.
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