Will liver of sulfur give a patina to plated rings?
The best way to find that out is to dip one and see what happens. Liver-of-sulfur does not work on steel, brass, nickle, nickle-silver, etc. If your rings are plated with copper or silver, it will turn them dark. HOWEVER, removing the excess patina with either a scrubbie pad or by tumbling may not only remove the patina, but may also remove the plating.