Sorry not sure if you can buy anything, but how about keeping the little packets of gel beads you get with new shoes , bags etc.
Would having a few scattered in your drawers help? never tried but in theory they should work.
I lived in a damp static caravan for a year when we were building, ended up throwing my whole wardrobe away... let me know if you find a solution
I think cameleon's advice might work - you can buy silica gel sachets - I think DH bought some a while ago and found that ebay was the cheapest place to buy them in bulk (well, bulk-ish - just one smallish cardboard box).