There's been a old unisaw sitting in my garage which I decided to rehab. It had 1/16" layer of rust and I lost my patience and took a sander to it. I think it worked out OK, but in uncovered these spots that had been covered by especially thick rust. They actually protrude above the surface and they appear to be as hard as the rest of the cast iron.
Can someone suggest on how they could be removed?
Thank you in advance.