Do keep a fire extinguisher and first aid kit within easy reach.Do wear safety glasses or goggles when cutting, drilling or prying, to prevent debris or foreign matter from getting in your eyes. If you wear prescription eyeglasses, wear also safety goggles or compatible safety glasses 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 jackstands for any under-vehicle service. Jacks are for raising vehicles; jackstands are for making sure the vehicle stays raised until you want it to come down. Whenever the truck is raised, block the wheels remaining on the ground and set the parking brake.Do use adequate ventilation when working with any chemicals. Also, the dust from certain aftermarket brake linings may contain asbestos, and should not be breathed into the lungs. Even trace amounts of this hazardous material is known to cause cancer and lung disease following a lengthy incubation period.Do disconnect the negative battery cable when working on the electrical system. The secondary ignition system can contain extremely high voltage.Do follow manufacturer's directions whenever working with potentially hazardous materials. Both brake fluid and 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 being done.Do when possible, pull on a wrench handle rather than push on it. Adjust your stance to prevent a fall.Do be sure that adjustable wrenches are tightly adjusted 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.