^ yeah, but those dessicant packs are cheap and reusable. buy a pack of 10 or 20, and just cycle them, 2-5 at a time. they're portable too, so they're always in the case even if the case is in your car or if there's a power outage that kills the heater. the other ideas are also great if the source is significant - but i'd still toss in a pack or three on a regular basis. i use them with all my camera lenses too - put lens plus one pack into a ziploc bag, suck out the air, seal, and store in (giant) camera bag. cheap extra protection!