DS has an air up (I know, hideously expensive and gimmicky but at least they have encouraged water drinking in school!) I have been washing with washing up liquid but when I looked closely tonight there was black mould in the mouthpiece as it has hidden grooves! I’ve thoroughly cleaned it and soaked in Milton. It will be ok to use afterwards won’t it? Or should I shell out for a new part (costs half the bottle!!) Not sure whether that’s necessary although I think to be on the safe side it probably is?!