Vehicle repair and maintenance is an industry that is considered to be a small quantity generator of potentially hazardous materials. The primary source of these materials is from cleaning and preparation activities. Cleaning fluids (steam jenny, high pressure hot water, etc.) are used to clean the engines, axles, transmissions and other parts. The cleaning fluids are then drained to an oil-water separator. The light oils are usually skimmed and sent elsewhere. Grits and sludges build up in the bottom of the oil-water separator, and it has to be cleaned out on a regular basis. The approach is to combine the oil, grease and grit sludges in sufficient volume to pretreat them safely and in a cost-effective manner.