COS is a technology that is the safest and most effective way to remove color from hair that is undesirable. In just 20 minutes, The Color Out System corrects and removes the color by shrinking the dye molecules, allowing it to be simply washed out of the hair. Levels are of no concern as COS's unique bleach and ammonia free formula removes all artificial pigments from the hair keeping the hair in great shape. Dennis Bernard's hair dye remover is so gentle that the hair can be recolored right after the COS service.