Household ammonia is an aqueous solution of Ammonium Hydroxide (NH3) in water. It is a caustic liquid that gives off a pungent vapor. It is used to make cleaning solutions for floors, walls, shower stalls, counters, stovetops and appliances. Mildew, scuff marks, tarnish and some stubborn clothing and carpet stains can be removed with ammonia. Available in: 24units / 2 fl oz (350ml) 4units / 1 gl