By the late 1980s, acid-washed jeans and denim jackets had become popular with both sexes. Acid washing is the process of chemically bleaching the denim, breaking down the fiber of the material, and forcing the dye to fade, thus leaving undertones of the original dye evidenced by pale white streaks or spots on the material. Severely bleached and ripped jeans, either manufactured purposely or done by hand, became a popular fashion trend, being a main component of glam metal music acts such as Poison.

Source: Wikipedia