Spontaneous Combustion of Oily Rags
Do-it-yourself projects often involve using products with high VOC’s (volatile organize compounds) which makes them flammable. Examples of these products are oil- based paints and stains, varnishes and polyurethane, paint thinners, etc. Oily rags have a long history of being a source of fire, because people are not aware that they have the ability to spontaneously combust and catch on fire. For a fire to exist, it needs heat, oxygen and fuel. Oily rags that get folded or balled up and tossed on the floor have the danger of going through a process that starts with oxidation. As the oil is drying on the rag, it produces heat, and air gets trapped in the folds or balled up portions. Heat and oxygen are combined in addition to the rag, which is usually made of combustible cloth that can become a source of fuel. Heat, oxygen and fuel are all that is needed to create a fire, which is why oily rags that are not disposed of properly can create a fire that people are not prepared for. 

How to Dispose of Oily Rags
Oil or gas-soaked rags should be safely disposed of after use using two steps: 

  • Hang them outside to dry in a safe area or spread them out flat, making sure they are weighted down outdoors. They should not be in a pile. 
  • Once they are dry, they should be disposed of properly. 
    • For somebody who uses oily rags on a daily or weekly basis, the oily rags should be placed in a listed oily waste container and emptied by a private contractor.
    • For a less frequent user, the now dry oily rags should be stored in a small, airtight, non-combustible (such as metal) container with a tight-fitting lid. An old paint can is a good example. The rags should be completely covered with a solution of water and an oil breakdown detergent. Do not add any other combustible material (stuff that can catch fire). The user should then dispose of the rags during a city-sponsored hazardous waste collection day.