I recently found a very pretty but extremely dirty (caked on mud and grit that’s actually adhered to the metal - it looks like it was buried underground for a few centuries) NA silver ring at a yard sale with a beautiful (I believe natural, as it has pitting and rough matrix inclusions) turquoise stone. I brought it home and tried to clean it with a toothbrush and plain tap water, which usually works with mild dirt, but even after scrubbing the grit is too caked on to budge. Is there any way to clean it without harming the turquoise? If it were plain silver, I’d leave it in a dish of jewelry cleaning solution overnight and hope the grit broke down and came off, but obviously I can’t do that in this case. Any suggestions would be most appreciated.
Thanks again and best wishes,