Verdigris test

Discussion in 'US Coins Forum' started by GSDykes, Jan 27, 2020.

  1. GSDykes

    GSDykes Well-Known Member

    About 5 years ago, "Desert Gem" (I think it was he), soaked some coins in a solution to test how long it took to remove or reduce some verdigris. Today (Jan. 27) I begin a test using 3 bronze (actually 4 counting the Fuel Injector Cleaning Fluid) cents, soaking one in:

    Virgin Olive oil

    another in
    Mineral oil

    and another in
    Distilled water

    On about Feb. 4, I will rephotograph them after about a 9 day soaking. I will finalize each with an acetone dip, then blow dry each, and then continue to see if the verdigris returns or??
    Here are 3 of the 4 coins before, showing Rev. and Obv, each is a bronze cent. Doesn't that 1927 look bad! One has its date covered, but I think it is a 1970 or 1980.


    to be continued, (OH, see below I am adding some more!!).
    Gary in Washington
    Last edited: Jan 27, 2020
  2. Avatar

    Guest User Guest

    to hide this ad.
  3. GSDykes

    GSDykes Well-Known Member

    Okay, another added. I am trying to keep it simple, with simple to find chemicals. I added one bronze coin into a
    Baking soda/salt/distilled water solution - 1/4 cup H2O + 1 tsp BS + 1 tsp salt

    and am showing an image of the
    Fuel injector cleaning fluid soak

    That 1973 is nasty! do zoom in!

    Gary in Washington
    Last edited: Jan 27, 2020
  4. Danomite

    Danomite What do you say uh-huh Supporter

    What brand of injector cleaner are you using?
  5. GSDykes

    GSDykes Well-Known Member

    Gumout - Fuel Injector Cleaner
    Thanks for reminding me to be more thorough!
    Danomite likes this.

    GDJMSP Numismatist Moderator

    I truly applaud your efforts for doing your own experimentation. But I think you should at least be aware that you are traveling down a road so well traveled that the asphalt, and even the cobblestones beneath it, have been completely worn away from all the traffic !

    Ya see, verdigris has plagued coins that contain copper for millennia. And people have always tried to find a way to combat it. And in all that time, to the best of my knowledge, there have only been 2 commercial substances (chemical compounds) found that will successfully remove it. One is Biox, the other is Verdi-Care (and its predecessor Verdi-Gone). Biox works, but it also harms the coin. Verdi-Care on the other hand does not harm the coin.

    Now there are other compounds, acids for the most part, that will remove verdigris, but they all harm the coin, some more than others. And some like olive oil, which contains a very mild acid, will remove a little bit of it but that's about it. Trying pretty much anything else is a waste of time.

    And, you also need to remember that once verdigris forms on a coin irreparable damage has already been done to the coin. And, you also need to realize that as long as you remove moisture from the equation, or at least limit moisture as much as possible with proper storage methods, the continuing development of verdigris on a coin is stopped dead in its tracks. You can leave existing verdigris on a coin for a thousand years, literally a thousand years, and it will do no additional harm to the coin.
  7. GSDykes

    GSDykes Well-Known Member

    Thanks for your input. Though others have gone before me, I am not daunted. WD40 was developed after many tests, beyond 40. Penicillin development required lots of failed tests, and of course the Salk vaccine required much failure. I realize that these tests have been done before, but not exactly in the same way as I proceed. Part of this demonstration is for the benefit of those who themselves have never experimented as such, and are therefore curious, for them mainly - I forge ahead.
    Another part of this demonstration, is illustrating how one protects the coins AFTER the chemical soaks, how to stop air and moisture from further contamination(s). But I am getting ahead of myself. How many current members have intimate knowledge of these basic tests? I already know some are curious, and have not been down the well worn road.
    Tests with Krud Kutter, Goof Off, electrolysis, et al, ketchup, vinegar, and other acids are not involved here. Though I may mix olive oil and vinegar someday for a test. I certainly do not intentionally want to damage the coins. Thus I proceed.
    Again thank you for your reminder(s).
    Gary in Washington
Draft saved Draft deleted

Share This Page