Haven't tried that but I had a bottom-bracket that I was cleaning and re-packing on my old bike that had some rust and pitting on the bearings. I flushed all the grease from them and then held them to the brush side on my bench grinder. It cleaned and polished them nicely. I repacked the grease and reinstalled them thinking it would be great but felt little improvement when I spun them. Wouldn't hurt to try though. At least until you can find new ones. Good Luck! DG