Do keep a fire extinguisher and first aid kit within easy reach.Do wear safety glasses or goggles when cutting, drilling, grinding, or prying, even if you have 20/20 vision. If you wear glasses for the sake of vision, then you should wear safety goggles over your regular glasses.Do shield your eyes whenever you work around the battery. Batteries contain sulfuric acid; in case of contact with the eyes or skin, flush the area with water or a mixture of water and baking soda and get medical attention immediately.Do use safety stands for any under-truck service. Jacks are for raising vehicles; safety stands are for making sure the vehicle stays raised until you want it to come down. Whenever the vehicle is raised, block the wheels remaining on the ground and set the parking brake.Do use adequate ventilation when working with any chemicals. Like carbon monoxide, the asbestos dust resulting from some types of brake lining wear can be poisonous in sufficient quantities.Do disconnect the negative battery cable whenever you are working on the electrical system. This is especially true when working on ignition systems which may contain EXTREMELY HIGH VOLTAGE. In some cases the voltage can exceed 50,000 volts.Do follow manufacturer's directions whenever working with potentially hazardous materials. Both brake fluid and ethylene glycol antifreeze are poisonous if taken internally.Do properly maintain your tools. Loose hammerheads, mushroomed punches and chisels, frayed or poorly grounded electrical cords, excessively worn screwdrivers, spread wrenches (open end), cracked sockets, slipping ratchets, or faulty droplight sockets can cause accidents.Do use the proper size and type of tool for the job at hand.Do when possible, pull on a wrench handle rather than push on it, and adjust your stance to prevent a fall.Do be sure that adjustable wrenches are tightly fixed on the nut or bolt and pulled so that the face is on the side of the fixed jaw.Do select a wrench or socket that fits the nut or bolt. The wrench or socket should sit straight, not cocked.Do strike squarely with a hammer. Avoid glancing blows.Do set the parking brake and block the drive wheels if the work requires that the engine be running.