Chlorinated brake cleaners contain powerful solvents like perchloroethylene, which make them very effective at degreasing and cleaning, but they’re also more hazardous to health and the environment. Non-chlorinated brake cleaners use solvents like acetone or heptane, which are less toxic but may be slightly less effective. For automotive maintenance, both types serve to clean brake parts, but it’s crucial to choose based on your specific needs and safety requirements.