Here is what I use. It's a product called Worley's Wonder. I've been using it for over 10 years. I ran into it at an expo years ago. They have me a free bottle of it , and I became a believer ! I use it on all my jewelry. I just cleaned some of my GEN Bracelets a few days ago. Check out the pictures.
This is after one spray down and a good wipe
I then sprayed it on again, and with a fine toothbrush, I got in between the lugs and got all the gunk out. This is after 2 months of usage. You can see all the crap that get's stuck in it.
This is one of my Gold bracelets soaking in the liquid for 30 minutes. Look at all the debris it gets out.
Here is the finished product. You be the judge
Here's a picture of the product. I buy it on Ebay dirt cheap for the huge bottle
I should do a write up on it.
More pics:
Here are some heads I cleaned with it for a customer of mine