DON'T run an engine in a garage or anywhere else without proper ventilation-EVER! Carbon monoxide is poisonous; it takes a long time to leave the human body and you can build up a deadly supply of it in your system by simply breathing in a little every day. You may not realize you are slowly poisoning yourself. Always use power vents, windows, fans or open the garage door(s).DON'T work around moving parts while wearing a necktie or other loose clothing. Short sleeves are much safer than long, loose sleeves, and hard-toed shoes with neoprene soles protect your toes and give a better grip on slippery surfaces. Jewelry such as watches, fancy belt buckles, beads or body adornment of any kind is not safe when working around a car. Long hair should be hidden under a hat or cap.DON'T use pockets for toolboxes. A fall or bump can drive a screwdriver deep into your body. Even a wiping cloth hanging from the back pocket can wrap around a spinning shaft or fan.DON'T smoke at ANY TIME when working on a vehicle, ESPECIALLY when working around gasoline, cleaning solvent or other flammable materials.DON'T smoke when working around the battery. When the battery is being charged, it gives off explosive hydrogen gas.DON'T use gasoline to wash your hands; there are excellent soaps available. Gasoline contains many chemicals which can enter the body through a cut or be absorbed through the skin, and accumulate in the body until you are very ill. Gasoline also removes all the natural oils from the skin so that bone dry hands will suck up oil and grease.DON'T service the air conditioning system unless you are equipped with the necessary tools and training. The R-12 refrigerant becomes a poisonous gas in the presence of an open flame. One good whiff of the vapors from burning refrigerant can be fatal.DON'T hurry. This means avoid getting yourself into a time trap because you didn't allow enough time to do the job or because you're working outside and the weather is changing. Working at a sensible pace, you're more likely to anticipate safety problems by thinking ahead and by using tools more effectively.DON'T lose track of your tools or parts. Wrenches left on fan shrouds and in the area of drive belts become potential missile hazards. Items like these often suddenly find their way to an eye, face, limb or the engine. Scan the engine compartment for any loose tools or any parts that may have been replaced. It's great to be able to fix your car, save money and get satisfaction, but it's not worth the price of personal injury!