"Oxidizing" a silver ring
Liver of sulfur, a mixture of potassium sulfides, is used to darken some areas of this silver ring decorated with musical notation. "Silver oxidizer" and "oxidation" are wrong terms, since this chemical reaction has no relation to oxygen. As liver of sulfur destroys brushes, I often use a sharpened toothpick to do this. Excess black coating will be removed as soon as it dries.
Mauro Cateb, Brazilian jeweler and silversmith.