If you don't frequently use the metal tools like hammers, screwdrivers and awls in your toolkit, they can rust over time. The smallest amount of moisture can attack metal tools in your toolbox. One way to prevent rust is to look to your backyard barbecue. Adding a few charcoal briquettes is a simple way to naturally dehumidify your toolbox. Charcoal is porous, so it absorbs odor and moisture. Just a few unlit briquettes will do the job to protect your tools.