I had a steam sterilizer but it broke which is a shame because it also had dryer function. So I have just been boiling to sterilize bottles and pump parts but when I leave them to dry theu get a chalky powdery residue, probably from the hard water in my area. What do you do with it rinse them with water. Does that defeat the purpose of sterilizing? Not so much worried about the bottles being rinsed but the pump parts because I freeze alot of the milk I pump.