To remove mildew from the interior of your dishwasher, mix one cup of Clorox bleach to 1 gallon of water. You can also mix a 1/2 cup ammonia with one gallon of water. Never mix bleach and ammonia. Mixing bleach with ammonia creates highly toxic and potentially lethal fumes. Don’t use chlorine bleach to clean the interior of your dishwasher if it has a stainless steel interior; bleach can corrode stainless steel. Always wear gloves when cleaning with bleach or ammonia. After creating the mixture appropriate for your dishwasher’s interior, wipe it thoroughly with a cloth or sponge. Run the dishwasher through a rinse cycle to remove any residual cleaner.