Or an angle grinderA nice file should sort them
Scrape 'em along the back door step.Or an angle grinder
This is why I was thinking chemical rather than mechanical, I can see a couple may have to be sacrificed in the name of Science! I'll try Evaporust first. I'll report back when its done.As soon as you touch a face with any abrasive it's no longer a standard.
Attack the rust spots only if you intend to actually use them for metrology
beadblast with fine media using a suction gun it does not impair tolerance or remove metal it just piens
We used to have a company in that used to blast CO2 pellets at our welding fixtures to remove all the built up weld spatter, they almost looked new when finished.That's an interesting idea. Might work too. Part of the commissioning process for the JWST mirrors was to blast the fine gold coated surface with frozen CO2. One of the most precise surfaces it is possible to produce. While CO2 might not do anything to those gauge blocks, something like bicarbonate of soda (coarse crystal) might shift the rust without damaging the lapped surfaces.