Ditto. I O2 clean my HP120s with glass beads and Simple Green and it takes care of the rust. Yes, after drying there is a minor amount of flash rust, but that is almost inevitable. I haven't been faced with heavy oxidation so I don't have experience with beads under those conditions.I tumble cylinders with inert glass beads to clean them for oxygen service. There will still always be some flash rust due to drying. Heavy oxidation will require diffent media.