This worked well on jewelry.  All the dull jewelry came out shining.  It also worked on glasses and did not seem to harm them.  due to the larger size, I cleaned several pair at once.  It did harm the film on a pair of tinted safety glasses, but I don't mind.  I used it to clean spark plugs on my lawn equipment.  It did not remove the carbon but it did get them very clean and I brus the carbon off with a wire brush.  It is now much easier to start the lawn equipment.  I also cleaned shaver and razor heads that I could not get completely clean.  They came out completely clean.  I used a couple drops of dish soap for all cleaning.  This unit also comes with a heater which helped in the cleaning process.