I was going through some of the coins in my collection and just noticed that one of them, a Nero sestertius, seems to have some faint corrosion along the edge. It looks pitted and light greenish. Bronze disease? It seems to be confined to the coin's edge. Part of what makes me suspect it is that the coin does have a scattering of deepish pits especially on the reverse that are clean. Is it possible that the stuff on the edge was missed in the coin's original treatments? Anyway, I'd appreciate any help or advice you might have. Thanks!
Have you taken a toothpick and picked at any of it and see if it moves easily? If so, it's BD and yeah, you will have to treat it. From the photo, it does look like BD.
hmm... could be. I don't think it is though. BD is usually a lighter green and powdery. I think it's just mineralization that's found some crevices/old corrosion to live in. The best thing to do in cases like this is take some good photos and leave it be for a while, periodically revisiting it. If you notice any differences later on (months, years), then treat it. The best course is usually do the minimum necessary.
Okay I just tried poking at it some with a dental pick. The green stuff scraped but didn't seem to come off very easily. Hard to see what is going on though; I think the pick is not quite sharp enough to get down into the pits very far. I'll try later with a sharper instrument and also keep a watchful eye on it. Thanks!
Doesn’t look like it to me. BD has an almost pastel green color, while this at least looks darker like a lot of green patinas.
Doesn't look as bright as bd, but if it was me I'd still let it soak in distilled water for a few days and give it a soft scrub with an old tooth brush. If it doesn't come off with that it isn't bd.
Most green on a bronze coin is stable and not only does not need treating doing so could damage the coin. This is particularly true when the coin is acquired from a reputable dealer who will treat a diseased coin before selling it. That said, if a patch of green suddenly appears and is light green in color it might be a sign of bronze disease. Please don’t use a dental pick on a coin. It’s never necessary. All you need to test for bronze disease is a toothpick. If the tip turns green after lightly tapping the suspect area then you have active corrosion. If that is the case, gently work what you can off with the toothpick. Then soak the coin for a few weeks in distilled water, checking the affected area with a toothpick until it stops being tinted green. Then treat the area with verdicare or equivalent.
its the right color but doesn't mean it is...you should treat it with some verdi-care for good measure
