To disinfect a backpack, confirm that the backpack is made of a bleach-safe material like nylon and confirm colorfastness to bleach, then presoak with a ratio of 1/3 cup Clorox Disinfecting Bleach per gallon of water just as you would to remove mold and mildew as described in our guide. To disinfect, you need to let the backpack soak for 6 minutes, then rinse or machine wash.