I have a silvered antoninianus
with some hard red
and green encrustation on both obverse
. In perusing the discussion board
for a solution, I came across several that seem to fit the situation.
First: the diagnosis: "Red
incrustations are usually composed of Cu2O (copper (I) oxide)"
So, bronze disease
1. "People say benzotriazole solution in ethyl alcohol
is a powerful inhibitor of copper corrosion. Benzotriazole can be purchased here: (link)
2. "[Put] into [distilled water] with Gringott's Bronze Disease
Killer on a low boil, followed by a long soak/pick/soak/pick cycle. For cleaning, I alternate between a dental pick
and a diamond tipped Dremel tool." I've not heard of this product before, or seen it for sale.
3. "Ammonia will remove it, slowly. The household ammonia will have to be changed after a day or two, and if it seems to stop working, it is probably because there is lime mixed in, so rinse, put it in vinegar for a day or two, rinse, and then go back to the ammonia."
4. "I would imagine a brief soak in lemon juice followed by a gentle rub would clean them off."
I've opted for solution #4 as the least aggressive approach, at least to start. It was a good
start, but not a runaway success
. Here's the result in pictures: Before
encrustation is still
there, but reduced
, and the coin is shinier. I tried to chip away at the encrustation (blackening Q-tip ear buds). I am tempted to leave as-is
. Suggestions welcomed.