I store my fixed blades out of their sheaths, in individual compartments in a Pelican Rifle case. Each blade is wiped down with Hoppes #9 prior to oiling with OTIS gun oil. I also have Vapor Corrision Inhibitor packs inside the case (covers a 500 square foot area...a bit overkill but hey!). In addition there is three cans of moisture-sorb silica. I change them out every few weeks, (i got 4 x 50lb bags of the stuff).
My folders are stored in their boxes inside a smaller Pelican case, same thing, VCI packs and moisturesorb packs.