According to Martha Stewart, mildew can grow in a washing machine, especially in humid or poorly ventilated areas. The problem’s usually around the rubber door seal. Start with a cup of chlorine bleach mixed with 2 cups warm water. Wearing protective gloves, wipe and clean the seal from bottom to top, paying special attention to areas where water may collect. Finish your disinfection process by running the washer (empty) with a hot cycle and a full bleach dispenser. Repeat every couple of months or when you see or smell mildew.