Sterilize the bottle, screw thread, and dust cap by boiling in a pot on the stove for 5 minutes. Be sure they are completely covered by water. Set out to cool and dry on a clean cloth.
Alternatively, you can sterilize by washing in sterilizing solution or by using a bottle sterilizing machine - check directions of the manufacturer in regards to use with glass bottles. Do not boil in a pressure cooker or in a microwave.
When bottle feeding babies up to 3 months, disinfect the feeding bottle after each use with the above methods. Once babies are over 3 months, you need only sterilize bottles with this method on a less regular basis, and at this time, you can also wash using warm water in your sink or via dishwasher (place on top rack).