If you are pumping, be sure to boil all breast pump parts that come in contact with milk for 20 minutes per day. (lovingmomentsbras.com)
You will need to wash and rinse any parts which came into contact with the milk. (expressing-mama.com)
In fact you don't even have to clean this bottle as it does not have direct contact with milk and serve only as a rigid structure holding disposable liners. (babygearhub.net)