There are a couple of vids on the linked site above (posted by Rondel), which demo how they clean up rusted/oxidized blades, as well as fixing the edge grinds and resharpening afterwards. Nice vids, including some cutting/slicing demos on tomatoes that are impressive. They use a 'rust remover' block device which looks as if it's similar to the above-mentioned 'rust eraser' blocks. I'm sure the 2k grit wet/dry paper would also work.
David