[Exhibitman]

Light is the big killer of cards, of course, but moisture also is a risk. Graded slabs are not watertight--I believe BVG's is closest. Kevin (onlychild) did some experimenting on them, I seem to recall, and BVG's was the best. I would not count on a slab alone protecting from moisture, though.

I look for a plastic (not cardboard or wood--water can soak into them) box with as close to a positive seal (seal that does not allow moisture to pass through) as is feasible and constructed so that the seam between the lid and the box is as close to the top as possible. In most cases that boils down to a seal where the box rim goes under the rim of the lid so that gravity-driven water would run down the side of the lid and fall off rather than getting into the interior of the box. PSA had these great plastic boxes that were opaque, had a positive seal, and held 25 slabs. Don't know what happened to those--I haven't seen them for a while offered by PSA. There are some food containers with built-in rubber gaskets that achieve a very strong positive seal. I have one called "Lock & Lock" which has a gasket and clips down on all four sides. I use it to go to the National and other shows just in case I get caught in weather while traveling. That happened once--Cleveland--and the cards stayed bone dry. Organize.com sells them. I also keep a number of those silica dessicant packs in my storage cabinet and safe deposit box. Although I live in a fairly arid climate I figure it is just good practice to control the humidity as much as possible.