Yeah, depending on what happens I may try a brass dremel brush first and then stainless steel for the M82. Waiting to hear back from a machine shop about them getting the staked screws out to start, as just due to the rarity of the scope I don't particularly want to to try it myself....
Speaking of "metal wires everywhere" I used to use cheap brass wool for cleaning light surface rust. I regretted it when that stuff fragmented everywhere, and I was feeling it in my socks for weeks. I recently discovered brass velcro brushes at a tack shop, and they have been lifesavers: Velcro Brush - PBS Animal Health (just as an example) super cheap, and they don't flake everywhere.
Other updates - I sold the M73B1 with the broken crosshairs to another collector who wants to try and do a full restoration (sourcing a correct tube alongside fixing the crosshairs themselves). The other M73B1 and M84 are completely cleaned as I posted pics before. I'm considering swapping the M84 onto my 1903A4 as its easier to remove and store without the scope that way. Right now I have a Lyman Alaskan B series on it. Maybe one day I'll track down a Lyman M73 or M81 marked scope to fill those holes in my collection...