Pro Tips: First, swish the soiled underwear around in a clean toilet. Then hang on to it and flush. The current will wash away most of the fecal matter. Next, fill the sink with hot water. Add a small amount of laundry detergent and approximately 1 tbsp. of bleach per gallon of water. Hand wash the soiled undergarment in the sink. Drain the fecal water. Rinse well with plain water. Hang the clothing to dry so it doesnâ€™t mildew. Wash the sink and disinfect with bleach. Add it to the next load of laundry and launder as usual.