I'm very interested! This is always a tricky issue. As vid1900 asks, is this removing the topcoat lacquer? You'd know if it was because the ME would be turning some sort of color such as yellow (obviously the pinball dirt would be grayish-blackish). Does it leave the surface dull or is the original gloss still there as compared to uncleaned areas? Would be killer news if this gets ground in dirt and ball swirls clean.