[special-K]

Sorry i haven't checked to see both of your suggestions. My slots were about black when I got them and I used over cleaner, and they weren't coated. I started with scotch brite but decided to wet sand with a fine paper using wheel cleaner. The backs look like crap but who cares? I did my best and they are "ok-ish". The diff cover I want to go the other way. Could have tried oven cleaner. That's actually an acid solution, right? So is wheel cleaner. I have had a partial gallon of muriatic acid from cleaning masonry. I poured into a plastic bucket, diluted with water, and put the cover in face down. Kept checking and eventually pulled out after a couple few hours. It's good enough and I'll let Mother Nature do the rest