Your breast pump needs to be cleaned after each use with warm soapy water or a Medela breast pump cleaning wipe. If you use your pump daily, it should be sterilized at least once a day. If you are not using it daily, it should be cleaned before after each use. You may sterilize your breast pump in one of two ways. The first way you can disinfect your pump parts is to put the pieces in boiling water on the stove for three to five minutes. Then allow them to dry completely before storage. The second option is to purchase Madela-brand microwave sanitation bags that will enable you to stick the parts inside a unique container and sanitize in the microwave. As always, you still have to make sure they're completely dry before storage.