I've been experimenting with plastic blast media on cast iron. It pops the paint right off but doesn't affect the texture of the base metal. It doesn't do much for rust though. For paint and some very light rust it seems to be the ticket, especially on antique items when you want to preserve as much of the original material texture as you can. Removal of heavier rust would call for chemicals or a more aggressive abrasive. I haven't tried it on aluminum yet, but I'm anxious to do so. I think it's going to be the hot tip for aluminum parts, I have a feeling it will remove the paint and old grime without giving the aluminum that satin appearance that other abrasives do. I will also try it on sheet metal, my hope is that it will remove paint etc. without putting any stresses in the sheet metal that can cause warping. I'll post when I know more. If you have any experience with this, please chime in. Kevin .