We use stuff from fleet farm called jungle jake. It's a
biodegradable degreaser. It does smell a little though. Way cheaper
than any commercial ultrasonic cleaner. The oakite sounds
interesting. Says it's for stripping metal parts and and cleaning
dairy tanks. There are different kinds of it.
Any clue what it does to pearls or opals? Which one you use?
As with any porous stones I don't ever put those in an ultrasonic in
the first place. The Oakite is pinkish in color.
Through my experience all metals don't have a reaction with this
except silver. When we do silver objects it can tarnish it if you
leave it in there too long.
Generally just swish it in there with the sonic running, rinse and
steam and you are good to go. For porous stones just use a toothbrush
with the solution to clean and rinse immediately.
GIA uses this in their JMA classes and it is terrific.
By the way, GIA calls it BCR. buffing compound remover.
I have few samples for The solution we use at Stuller. If you like a
sample please let me know off line.
Andy "The Tool Guy" Kroungold