Skipbreather's suggestion is right on. I experienced the same situation with mine last July and being a kind of do, then think about it type. I just rubbed it with a fine piece of steel wool I had available. Mistake!!! a few weeks later I had the misfortune of finding out why, the solonoid stuck open on my dive. A couple of days later I disassembled the solenoid just to find a piece of the steel wool. The use of the scotch pad is a great idea.
Gabe
