I found some old pennies by an old spring this weekend. One is a 1917S
wheat penny. The ground they came out of was highly mineralized. On their
surfaces, the pennies have black oxidation.
Is there a way to take off this corrosion? I really don't want to use any
chemicals, as it may eat at what copper is left.
I have seen programs on TV where old coins found in shipwrecks are cleaned
electrolytically by passing a small current through them.
Does anyone know how to do this, or can steer me in the right direction?
Steve
Coin collectors use olive oil or mineral oil to clean up dirty coins.
If you want to try reverse plating, use a copper sheet anode in a
plastic bucket. A 12 V battery charger and a tbsp of sodium carbonate
[washing soda], or sodium bicarbonate/ gallon for electrolyte.As I
remember, the positive goes to the copper anode, but I could be wrong.
I've had limited success on rusted steel tools using an iron anode.
bugs
Just remember - most coin collectors will tell you that cleaning destroys a
coin's appeal.
Don't worry, though. Your wheaties are worth less than a buck, anyway:
Nope.
Keep 'em as is. Any attempt to clean them will make them worthless.
The surface is part of the history of the coin. A 1917S isn't a key date,
but it's still not something you'd want to damage by cleaning.
Dave Hinz
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