. Apparently, Niels Bohr put his Nobel prize in Aqua Regia and stored it in an impervious container, maybe glass, for the duration of World War II. He returned to his laboratory when he went back to Denmark, and gave the dissolved medal to the Nobel committee, who made him a new medal from the material. I'm not sure what purity gold the Nobel medals contain.
I'm wondering what would happen to a binocular if you put it in Aqua Regia.
Amateur astronomy reflecting telescopes that are used by coastal observers need fairly frequent recoating.
I would also be more than a little worried using fluorite or fluoride lenses and scopes in a coastal environment.
I had a 20.5 inch Newtonian which I stored in my garage. Within a week from new the coating had been stripped from the exhaust fumes of the classic Saab.
Instead of backing the car into the garage afterwards I drove the car into the garage the other way round.
Incidentally, I just found out that the mirror of this telescope was one 20th wave, which I find quite remarkable. I didn't pay for this quality. The mirror maker is just very good.