I had a friend that used to use electricity to change the color of metal for jewelry. He did this about 10-11 years ago. It was pretty neat to see him change the color of metal from green , red, purple, blue, to multi color using water and electricity. There was probably a few other steps that I don't remember seeing, but I remember the water and electricity. He used several combinations of negative and positive shock on the jewelry to change the color. It was bad ass. One combination would make it look like that valve color and the wheels posted above.