This waste audit study investigated hazardous waste reduction methods for mechanical equipment repair shops in California classified as SIC Code 7699. The voluntary audit studies, including 35 telephone audits and 12 site audits, focused on repair shops' processes and operations, wastes generated, the treatment and disposal methods used, and potential waste minimization techniques. The study identified spent solvents, used oil, contaminated rags and sump waste as the main waste type generated by the repair shops. Waste minimization through source reduction can be achieved by good housekeeping, chemical substitution, and mechanical paint removal. Recovery of scrap metal and recycling of oil are also practiced. Illegal practices used by shops to manage waste, waste management costs, and state regulatory issues were also discussed.