Removing the film from metal reels & cans helps somewhat. Last year I had 2 B&W 16mm films of TV shows from the 1950s transferred to DVD, and the owner of the shop told me that ideally the film should be on a plastic reel, but he told me I should at the very least take the metal film reel w/film out of the metal can and put it in a plastic bag. I use the kind with a drawstring, and allow it to vent at the top. One of the films has VS, the other one doesn't (different stocks, I guess) so I keep the one with VS in a different room. :-/