When used in closed places (where mold, mildew & fungus live and breed) silica gel whisks away moisture to create a protective environment of dry air. It prevents all forms of rust, corrosion, oxidation, mildew, fungus, mold, fogging, etc. Silica Gel is used to prevent tarnish on gold and silver, in your tool box to protect your precious tools from rusting, or drop some in your camera bag to protect your camera and equipment. It even protects expensive leather items like jackets, shoes, and boots. Also great for tackle boxes, photo albums, computer media storage, gun cases, ammo boxes, coin collections, camping gear, backpacks, campers, electronics, etc.