These words mean to clean something so as to free it of germs, pests or other unhealthful encroachments. Sanitate indicates to make hygienic by thorough cleaning, with the implication that anything unfavourable to health has been removed, especially anything that might spread infection or disease: a ruling that second-hand clothes must be sanitated before being resold. This word appears to be giving way to the American. Sanitize either through affectation or in keeping with other –ize verbs: a special unit for sanitizing toilet seats. Sterilize specifically suggests the destruction of germs, that is, bacteria or micro-organisms that cause infection or disease: the high temperatures used to sterilize surgical instruments; sterilizing the wound by applying antiseptic. Disinfect is even more specific; although the word indicates the same action as sterilize , it implies the presence of an infection or of infection-causing germs: a liquid designed for disinfecting toilet bowls; an antibiotic that would act to disinfect the inflamed tissue.

Fumigate means to subject to smoke or fumes in order to kill germs or insect pests: to fumigate a sickroom to prevent the spread of contagion; to fumigate a flat by spraying it with insecticides. Decontaminate may sometimes apply in a general way. It has gained a specific meaning that refers to the destroying or neutralizing of poisonous chemicals or radioactivity that has pervaded an area: terms sent in to decontaminate all but the central area irradiated by the atomic explosion.