Brake cleaner is a cleaning agent that is mostly colorless and used for cleaning the brake disks, engine compartment, and underfloor of motor vehicles. It is used for removing oils, fats, resins, tar, and dust, mainly in the automotive sector. There are two main types of brake cleaner: chlorinated and non-chlorinated. The composition of chlorinated brake cleaners includes organochlorides like tetrachloroethylene and dichloromethane, while non-chlorinated brake cleaners use hydrocarbons as a main component, which can either be a low-boiling aliphatic compound or higher-boiling hydrocarbon mixture. Aromatics like benzene, toluene, or xylene may also be used. The hydrocarbons used are sometimes made by hydrogenation from naphtha. Some products also contain polar solvents such as ethanol, methanol, isopropanol, and acetone in order to dissolve non-lipophilic substances. Brake cleaners contain toxic compounds and should only be used in well-ventilated areas and with proper safety equipment.