Sorry to hear about your
aes grave. A photo would
help, because often a "cured" coin will show signs of former
bronze disease.
Bronze disease is easily misdiagnosed. Were these green spots powdery and sitting within pits in the
patina, or were they hard and sitting on top of the
patina? The former is likely
bronze disease, the latter not. Did they appear suddenly, or have they been there since you've owned the coin? Most 8mportant, have they changed (grown or spread) over time?
Moisture in the air encourages
bronze disease. You should take precautions to eliminate excess moisture from the coins' storage environment. I use two renewable (3 hours in the oven) dessicant pouches, which I regularly rotate in my safe deposit box. Whenever I visit the bank box, I switch the old pouch with a renewed pouch.
As for other actions to avoid spread, you might want to wipe-down (and thoroughly dry) the storage surfaces with which this
aes grave had direct contact, including the underside of any upper tray. I don't think
bronze disease is "airborne" like the flu (except that ambient moisture can trigger it), so I would only be concerned about direct contact with the green particles.
After soaking your coin in distilled water, you should thoroughly dry it in a LOW temperature oven for an hour or more. You might want to put some Renaissance Wax on your
aes grave after cleaning it, to seal out moisture; but I'd recommend watching it first, for a few months or a year, to see if the problem returns. If it
comes back, consider more aggressive treatment.
I
hope that helps.
