Upon evaporation they produce a vapor that, in sufficient concentration, kills both clothes moths and carpet beetles. The mere odor of the chemicals does not repel the insects and is no indication that the concentration of vapor is sufficient to kill them. If you store woolens in a closet without first placing them in containers, see that the closet is tightly sealed. If there are cracks around the door, seal then with tape or fit the door with gaskets. If there are cracks in the closet walls, floor, or ceiling, fill them with putty or plastic wood.
Protection is lost if the closet door is opened frequently.
In a trunk or closet, use 1 pound of the crystals, flakes, or balls for each 100 cubic feet of space. Because the vapors are heavier than air, the chemicals should be placed in a shallow container on a shelf, or suspended from a clothes rod or hook in a thin cloth bag or perforated container. You can also protect woolen articles by wrapping them in paper or sealing them in a cardboard box. Before wrapping or sealing, be sure the articles are not infested. In making a paper bundle, carefully fold back and seal all edges of the paper with paper tape.