Before starting a home improvement project that involves oil-based paint, stain, varnish, polyurethane, linseed oil, teak oil, or similar products, make a plan for safely storing and disposing oily rags. As oil-based products dry, they release heat. When rags are bunched together, that heat can build up and cause the rags to ignite without a spark or flame. This “spontaneous combustion” has caused multiple fires in Piedmont over the past three years.