I've found a use for all those little packets of silica gel you get in everything you buy (the ones that say "THROW AWAY. DO NOT EAT"). I collect them in the back of the drawer where I keep my razors. The drawer is not in the bathroom. The bathroom is too humid.

In a pinch, a handful of ordinary rice wrapped in a paper towel is an OK dessicant.

For the truly fanatical, a guy I work with swears by Bullfrog vapor-phase corrosion inhibitors (google it). I never tried them myself but he keeps one in every drawer of his tool box & thinks they're great.

I've never had any rust problems yet.