I have acquired a used tool that has some rust on its cast iron surface. I was thinking about using my RO150 to remove the rust with sandpaper. I have brilliant grits from 80-400 and platin grits from 500 to 2000. Would starting at 320 and working my way up through 2000 (in rotex mode) work well? Has anyone tried this? Is lubricant suggested or required? Thanks!