I would pull the cylinder and all the guts. use earplugs to plug the barrel at each end. put the sideplate back in place and tape over the openings for the trigger, hammer, cylinder stop,firing pin, thumbpiece, and hand.Also where the mainspring goes up into the frame. Some of those larger openings I'd use newspaper balled up tight and jammed into place. Also mask off the yoke cut. Remove the cylinder assembly & mask both ends of the cylinder after removing the extractor. Plug both ends of the extractor hole in the yoke.
Whew-- makes me tired just thinking about it! Probably why I haven't followed through and done it, as I've been thinking about bead-blasting one of my model 36's and matte blueing it using oxpho. Already did the cylinder due to massive blue damage and it came out good. I've also thought about blasting my model 60 for a matte finish, but the bead-blasters I have access to have been used for steel parts so I'd have to buy new media and make sure there wasn't any of the old stuff in there. PITA so I haven't followed through on that either.
Lots easier to just think about it.