Posted 01/20/2014 11:43 pm
If it's just dust, a simple brush-off should suffice. I assume we're not talking proof coins with pristine surfaces, so an airbrush or soft horsehair brush isn't going to hurt.
On the other hand, if the "dust" is really dirt, you'll probably need to wash it off. Dirt will come off in water (but use distilled/deionized, rather than tap water or rainwater). Don't rub away at adhered dirt with a cloth or tissue, since there might be little bits of rock stuck in the dirt that can scratch away and gouge into the metal if handled carelessly. A wash bottle, Water Pik, water pistol or some similar device that can generate a jet of water might come in handy.
On the third hand, if it's actually corrosion, you'll need to treat the corrosion.
Avoid using soaps or detergents, especially on lustrous untoned coins. They often contain sulfur compounds that accelerate toning. if not washed off thoroughly. Use them only if you can be sure they are sulfur-free.
On the other hand, if the "dust" is really dirt, you'll probably need to wash it off. Dirt will come off in water (but use distilled/deionized, rather than tap water or rainwater). Don't rub away at adhered dirt with a cloth or tissue, since there might be little bits of rock stuck in the dirt that can scratch away and gouge into the metal if handled carelessly. A wash bottle, Water Pik, water pistol or some similar device that can generate a jet of water might come in handy.
On the third hand, if it's actually corrosion, you'll need to treat the corrosion.
Avoid using soaps or detergents, especially on lustrous untoned coins. They often contain sulfur compounds that accelerate toning. if not washed off thoroughly. Use them only if you can be sure they are sulfur-free.
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
Once again.
