Someone
suggested Brownells' gel packs, which is a thought, but I was
 specifically interested in the little white bags/plastic canisters that
 I can just toss in a box. 
 But I must wonder if this will serve our purposes.  One little
 pack only absorbs only a small amount of water - then it stops. 
 
I was thinking a larger quantity, though ^_^
  I think these things are meant for closed boxes going
from
 factory to shipping container to warehouse to store, and
 shouldn't be expected to reduce humidity by significant
 amounts over long durations. 
This does make me lean more towards the Brownells' devices, which are
"rechargeable" (but somewhat expensive given the number of equipment boxes
I've got).
--
---------------------------------- personal: 
http://www.armory.com/~spectre/ --
 Cameron Kaiser, Floodgap Systems Ltd * So. Calif., USA * ckaiser(a)floodgap.com
-- Do not innovate unnecessarily. -- "The Tick" -------------------------------