How to Clean a Smelly Washing Machine...Clean the washer's lint trap with every load. (I didn't even know my washer had a lint trap!) Run a hot cycle WITHOUT clothes, add 3 cups distilled white vinegar to the cycle to clean out any bacteria. To keep the musty smell from coming back, occasionally add 1 cup vinegar to a load of towels. Also, run an occasional chlorine bleach load w/ hot water to keep musty smells at bay. Do it once a week w/ a load of whites.