Corrosive chemicals can either cause severe burns to skin and eyes or can severely damage metals. They begin to cause damage as soon as they touch the skin, eyes, respiratory tract, digestive tract, or the metal. They might be hazardous in other ways too, depending on the particular corrosive material.
Most corrosives are either acids or bases. Common acids include hydrochloric acid, sulfuric acid, nitric acid, chromic acid, acetic acid and hydrofluoric acid. Common bases are ammonium hydroxide, potassium hydroxide and caustic soda. Many of the everyday household chemicals can cause burns and should be handled with care e.g. bleach and oven cleaners. It is important to read the label carefully before use.