Woodworkers like us use all sorts of oil-based substances, such as finishes and lubricants. Fires caused by the spontaneous combustion of oily rags and waste are more common than you think. Don't even think of tossing such things in your garbage or leaving them laying about. The best way to safely dispose of oil or solvent-laden waste material is to keep it in a tightly sealed metal container. If you generate a large amount of this kind of waste, a commercial grade disposal can may be the answer. But if you are a hobbyist like me, the amount of waste can be kept in a small container.

A one gallon metal paint can with a friction-fit lid is ideal. You can buy a clean, new gallon can for a couple bucks at any paint store or home improvement center. Put the oily rags inside and press the lid on tight. The amount of air trapped inside the can will be enough to dry the rags, but not enough to support combustion. After a few days, the rags inside will be dry and you can safely remove them for disposal.