Boiling/ice water?

NMsilver · Aug 17, 2011

Has anyone ever tried or heard of taking corrosion off pennies by alternately boiling then plunging in ice water?
My reasoning is that corrosion, specifically the light green lumps (copper carbonate?) and impossibly hard crud is more brittle than copper and may "crack off".
I'm going to try it on some expendable wheaties, I love experimenting.

SBA701 · Aug 19, 2011

Keep us posted on how that works.

emfederin · Aug 19, 2011

NMsilver said:
My reasoning is that corrosion, specifically the light green lumps (copper carbonate?) and impossibly hard crud is more brittle than copper and may "crack off"

Your reasoning is sound in principle. If you manage to dislodge heavy patina through thermal shocking (and there's a good chance that it will), it WILL "crack off".

But since the carbonate replaces the copper, it's also the material that retains the detail. When the patina falls away, so does the detail.

AJinNJ · Aug 21, 2011

Another detectorist mentioned this same technique (method) to me the other day. Let us know how it turn out.

NMsilver · Aug 28, 2011

It worked on one

Wheat very well.
It turned a nasty brown 1930's wheat into a beautiful coin with a light amber patina but I think it was just the boiling that took off old residue.
It didn't affect the green globs on the other ones (or lighten up the dark brown patina).
I guess its just a gamble whether it works or not.

Boiling/ice water?

NMsilver

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SBA701

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emfederin

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AJinNJ

NMsilver

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