The "professional" way to clean coins?

Discussion in 'Coin Chat' started by mikkomakk, Sep 3, 2019.

  1. mikkomakk

    mikkomakk Member

    I've googled and looked around, to no avail!

    My questions is: How does "professionals", if you can call them that, "clean" coins which comes straight outta the dirt?

    Yes, we all know to NEVER clean a coin which is in decent condition, but what about one that is covered in dirt?

    I'm asking because I think electrolysis might do the trick without causing damage to the coin itself. I have tried this on certain cheap coins, and there is an extreme amount of dirt which comes off. It doesn't really leave any trace of cleaning, besides the color becoming different.. maybe to it's original state?

    Basically, there's a need to clean coins without touching the coins, and without covering them in oil/vinegar etc. I also tried white vinegar btw, and compared to the electrolysis and the vinegar did next to nothing in the span off 6hrs, while 10 min with electrolysis made it perfectly clean.
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  3. Orielensis

    Orielensis Well-Known Member

    Professionally cleaning ancient coins coming from the ground is a science of its own. Since electrolysis or harsh chemical cleaning will strip a coin of its patina, most high grade coins are cleaned (semi-)mechanically. There are different approaches and techniques. This guy, for example, does a pretty good job cleaning a late Roman bronze coin:

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  4. mikkomakk

    mikkomakk Member

    Ah yes, I remember the patina becoming quite different now that I think about it. Semi-mechanically seems to be the way to go then. The way he does it looks pretty to be a great way, but this definitely requires some skill.

  5. Conder101

    Conder101 Numismatist

    Electrolysis works by striping a layer of the metal surface off the coin which takes the dirt on that surface off as well.
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  6. calcol

    calcol Supporter! Supporter

    There are books devoted to this topic. A few are listed below. Cal

    Welter, Gerhard, Cleaning and Preservation of Coins and Medals, Hans M. F. Schulman, New York, 1970

    Frank, Charles, Coin Preservation Handbook, Coingard Industries, Brooklyn, 1964

    MacDowall, David William, Coin Collections, Their Preservation, Classification and Presentation, UNESCO, Paris,1978

    White, Weimar W., Coin Chemistry, 3rd. ed., American Sports Media, Rochester, NY, 2012
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  7. mikkomakk

    mikkomakk Member

    So a complete layer as well then? Because the surface afterwards didn't look spotted or anything after.
  8. mikkomakk

    mikkomakk Member

    Oh, great! I'll see if I can get my hold on one of those. Thanks :)
  9. calcol

    calcol Supporter! Supporter

    I think the UNESCO book can be downloaded for free. The others might be on the Newman Portal.
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