Cleaning Zinc Coins - Results To Date

Discussion in 'Coin Chat' started by kanga, Aug 13, 2020.

  1. kanga

    kanga 65 Year Collector Supporter

    Test 1 - 5 coins
    I totally botched the test.
    No scans before, hence no comparison possible after.

    Test 2 - 5 coins
    I botched 80% (4 out of 5) of the test.
    Therefore only one "before and after" comparison possible.
    Here it is:

    Obviously the white spots were "changed".
    But what disturbs me the most at this time is that the dark areas were lightened -- considerable.
    Pure Guess: The dark areas were only mildly affected over time (75-80 years), but my treatment resulted in a light coating of ZnO.

    I've got more zinc coins to fuss with so this is not over.
    I just need tighter standards for my process.
    My college chemistry classes were about 55 years ago.
    I've forgotten about careful control and recording of my testing parameters.
    At least I'm not going anywhere thanks to COVID-19.
    GH#75, Insider, TuckHard and 2 others like this.
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  3. Mountain Man

    Mountain Man Well-Known Member

    What are you using to clean them with? I must have missed your initial post on cleaning these.
  4. kanga

    kanga 65 Year Collector Supporter

    White vinegar (5%) for 6 hours.
    Next test I'll cut the time to 1 hour.
  5. Michael K

    Michael K Well-Known Member

    Oh white vinegar is going to make stuff whiter. Nickel, zinc, etc.
    You may have to dilute it to 2% and reduce the time as you mentioned.
  6. kanga

    kanga 65 Year Collector Supporter

    I need something acidic to remove the ZnO.
    Or I could rub the heck out of it.
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