Normally a sand-silica mix, the material is shot out of a compressor at an object to remove paint, graffiti, dirt and grease or even varnish. Both fine and course sand can be purchased, depending on the intended use. One problem with sandblasting is that it has a reputation for bending the sheet metal on cars and can actually blow holes in aluminium and thinner metals. Although it can be used sometimes for wood projects, it is recommended to implement soda, which is a much softer media. Common items that are sandblasted are concrete, greasy automotive parts and frames, steel projects and even vehicle bodies being prepped for paint.
Compressed air is used to propel the sand at the object to be blasted. More PSI (pounds per square inch) means faster travel and a more abrasive action. Sand works to force the topcoat off an object, whether it is paint, grease, or rust--almost anything. Some sandblasting can be successfully done, using a common backyard or garage air compressor found at any hardware store. However, there may not be enough PSI available for certain tasks, so be sure and ask around before you start. The normal do-it-yourselfer can probably get away with using 80 PSI coupled with a 3-mm nozzle. The drawback to this method is that it is pretty slow, but the benefit is that it will not heat thin body panels or other metals enough to warp them in most cases.
Be sure and cover your entire body with thick clothing because the media is guaranteed to bounce around and can harm you easily. Anything that will remove 30 years of paint and grime will have little trouble breaking skin. Special hood can be purchased for blasting and should be considered a must. Also highly recommended is a respirator. When the media breaks up into a fine dust, it can get into the lungs and cause problems. A cheap respirator can be picked up at any paint store or on the Internet. Do not blast where something other than the object can get damaged. Try and enclose the area with tarps or other barricades to keep the sand localised for cleanup.