Sanitize your Medela breast pump before you use it for the first time to protect you and your baby. You may find yourself needing to sanitize it at other times as well, particularly if you develop thrush or if your pump comes in contact with anything unsanitary. Following the correct sanitizing instructions will keep your baby healthy and prevent your breast pump parts from breaking down.
Rinse all parts that will come in contact with breast milk, including the flanges, valves and valve membranes. You don't need to sanitize the tubes, although it won't hurt them.
Fill a pot with cold water, as starting with cold water will help preserve the parts. Put the flanges, valves and membranes in the pot and bring the water to a boil. Boil for 10 minutes. Your breast pump accessories are now sanitized.
Wash the parts in hot, soapy water after each use. Rinse in clear water and air dry. You can also wash Medela pump parts in the top rack of the dishwasher.