Jewel Brite is an excellent cleaner and we have been using it for years!
It can be very difficult to find jewelry cleaner that is safe for pearls, opals, and other soft stones. You can also use it on gold and other metals. It is safe enough to use on costume jewelry, it won't break down glue.
The "biodegradable tarnish remover" is the key to the cleaner. I use an old tooth brush and water to gently scrub away the tarnish with the remover. You can then put the jewelry in a bowl of water and the black tarnish will rinse off.

Please feel free to reach out to us with any questions, we're happy to help.