The clear elastics are the worse for changing colors, folowed by the white and the tooth colored. The silver keeps it color the best. I would not recommend using any whitening agents because the center of your tooth is covered with the bracket. If you whiten the tooth around the bracket, when the braces come off you could have a darker spot on the center of your tooth. My advice is to avoid foods and liquids that discolor the elastics. Coffe, tea, chili, spagette, mustard, and so on.