Hi, I've picked up a set of stock 2.2 turbo pistons. They are incredibly dirty. Is it safe to blast them with any sort of media? I'd think walnut would be safe, is there a coating I do not want to remove? Out of curiosity, what are the consequences of removing the coating. Also, I've tried many chemical cleaners in the past, the ones I've tried did okay, but I want them spotless.