OTF
Coney Island Whitefish Biologist
I work with (and design) a lot of camera housings and o-ring seals in general. I lube the o-rings on my cameras. You're right that grease, especially if you use too much, does indeed pick up lint/hair/sand. Camera housing seals need to be inspected and cleaned regularly. I take out the o-rings and rinse them off in the sink, running my fingers around the whole rings to wipe off any old grease and debris before relubing and reinstalling. I also leave the housings closed to keep junk off the orings.