Best way to restore patina?

What is the best way to restore patina? I have a shadow box ring that I recently acquired that was actually caked with filth and dirt. Some of the darkened patina in the shadow box area was removed when I was trying to get out the filth. What is the best way to restore this? I have read about different methods online, but I would like to know what seems to give the best results.

Many of my friends use liver of Sulphur to add patina to the silver jewelry they make.
They say it is the easiest and best thing to use, especially if there are stones in the jewelry.

Plain old Clorox bleach works. Just be careful not to allow the bleach or other oxidizer to come in contact with stones, use proper protective gear, and rinse thoroughly with water when finished.

Best to test a small patch on the back of the piece first.