heating is still the best way. You can use HCL to remove mercury from the
surface of gold rings, but the trouble with this is that the mercury will
penatrate into the gold, while the acid will only affect the mercury it
can reach at the surface, without penatrating much into the surface. So it
won’t get all of it unless your rings went into the acid almost immediately
after the mercury got on them, before it had a chance to penatrate much.
Solution: Take a portable torch, like a plumbers cheap propane torch or
something, and take it outside, on a day with at least a slight breeze.
Anneal your rings to a dark dull red color, while standing upwind of the
process, and hold your breath if you wish while doing it. It really is
quick, and this way, you won’t be breathing any of it.