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Chances are slim they will continue to tone inside a plastic ziplock. Air and moisture exposure have a lot to do with the toning process.
Agreed. Your best bet to turn them all green is to leave them in an open jar or bucket, preferably somewhere damp like the laundry, basement or shed. You also want the layer of coins to be quite deep, so the weight of the coins on top can squeeze together the coins on the bottom.
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What colours would you expect to see and after how long?
They should turn a greenish-blue colour. The most "contagious" forms of verdigris are the paler colours; the darker malachite or emerald-green is usually quite stable and uncontagious.
The process should take a few years. Give them a good shake 'n' stir every few months, too, to break off bits of the green stuff and spread it from coin to coin.
You can try to accelerate the process by exposing the coins to the vapours from a volatile acid. The green pigment for mediaeval-era green paint was produced by exposing copper to acetic acid (vinegar) fumes for several weeks. Copper acetate is, however, water-soluble; "real verdigris" doesn't simply wash off in water. Hydrochloric acid fumes would probably produce some really strange colours. Sulfuric acid (battery acid) probably isn't volatile enough to get you much of a result.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
Posted 02/19/2010 2:13 pm
