So, what have you tried on the blade?

I start with 000 steel wool and WD40, then test with a hard backer, (wine cork or rubber bushing) and 1k Wet & Dry. That will give you a good idea how deep the pitting is.

If you are going to leave some pitting, treat the blade with EvapoRust to stop the rust.

600 Wet and Dry will get a lot of that and will easily polish with 1k then metal polish, (Mothers or Maas), or Chrome Oxide on a buffer.