The most effective stink bombs are those that contain a mixture of several stenches of biological origins. The biological odors used – vomit, human waste, body odors, burnt hair, and rotting garbage – are found universally revolting by people of all cultures. A mixture of various odors is more effective over time than a single odor, because it is much easier to acclimate to individual smells; a mixture therefore lasts longer and offers a greater impact.
The Guinness Book of Records lists two smelliest substances. One is the "US Government Standard Bathroom Malodor", a mixture of eight chemicals with stench resembling human feces, only much stronger, designed to test the efficacy of deodorizers and air fresheners. Another one, "Who me?", is a mixture of five sulfur-containing chemicals and smells like rotting food and carcasses. Pamela Dalton of the Monell Chemical Senses Center has combined the worst of the two to make "Stench Soup"
Prank stink bombs and perfume bombs are usually sold as a 1- or 2-ml sealed glass ampoule, which can be broken by throwing against a hard surface or by crushing under one's shoe sole, thus releasing the odorous liquid contained therein. Another stink prank product, Liquid ASS, comes in a small bottle and is applied to objects with a fine stream by squeezing the bottle. Since Liquid ASS does not use sulfur, it has a genuine smell of feces and rotting flesh. Another variety of prank stink bomb comprises two bags, one smaller and inside the other. The inner one contains a liquid and the outer one a powder. When the inner one is popped by squeezing it, the liquid reacts with the powder, producing hydrogen sulfide, which expands and pops the outer bag, releasing the putridity.
At the other end of the spectrum, the governments of Israel and the United States of America are developing stink bombs for use by their law enforcement agencies and militaries as riot control and area denial weapons. Using stink bombs for these purposes have advantages over traditional riot control agents: unlike pepper spray and tear gas, stink bombs are believed not to be dangerous, and they are effective at low concentrations.
The most often encountered compounds are: