Cotton swabs (British English: cotton bus) are used in first aid, cosmetics application, and a variety of other uses. They consist of a small wad of cotton wrapped around the end of a small rod, made of wood, rolled paper, or plastic. They often come in many different colors such as pink, blue, and sometimes even yellow. The most common type of usage is to dip the cotton end in a substance, then use the swab as an applicator for the substance. Sometimes swabs are also used for removal of substances such as earwax from ear canals, though the instructions accompanying the swabs generally contain a warning that the swabs should not be inserted directly into the ear, as doing so is actually dangerous, and has proven to be fatal in at least "four or five ... cases".