Bottles should always be washed in hot, soapy water and should be rinsed thoroughly to remove any traces of soap. The bottle including the screw threads, nipple and nipple rings should all be scrubbed with warm, soapy water and with a bottle brush. Hand washed bottles should be rinsed thoroughly with hot water and be allowed to air dry.
Bottles may also be placed in the dishwasher. Rinse bottles and use a bottle brush on them before putting them in the dishwasher to remove milk protein that builds up over time. Bottle nipples should be turned upward to prevent water from accumulating in them when placed in the dishwasher. Bottles can be dried on the hot drying cycle of the dishwasher to sterilize them.
Generations ago parents sterilized bottles before each use. Today some experts recommend boiling bottles and nipples for 5 to 10 minutes prior to their first use, others recommend boiling them more often and others believe boiling is unnecessary. Nannies should discuss bottle cleaning and sterilization procedures with their employers to best understand their preferences.