I have three heirloom knives, two with carbon blades, one with stainless, but with what appears to be celluloid handles. I store all of them in ziplocks.
On the carbon steel knives, I keep the blades & springs coated with renaissance wax (you can Google to find a supplier), then I keep a desiccant pack in the ziplock with each one.
On the stainless knife (an old Schrade/Walden rigger's knife, early 1960's) the handle material is pretty much disintegrated, so I'm not too worried about trying to save the handle material; I keep a desiccant pack in that baggie as well, and after reading an article on celluloid in the 2004 Sporting Knives (article by Richard White) I started switching out the desiccant pack every six months or so. No further deterioration so far. I don't know if the desiccant soaks up any "bad" gases the celluloid might put out, but it seems to help.
thx - cpr