I play a reed instrument, although not oboe. I have never had problems with the salt content in my saliva effecting a reed before, though my (sax/clarinet) mouthpieces tend to get dirtier than most other musicians'. What I can tell you is that of all the reed instruments, oboe and bassoon have the most sensitive reeds due to the fact that they are double reed instruments. Whereas sax and clarinet reeds vibrate against a plastic or metal mouthpiece, the oboe and bassoon reeds vibrate against each other, making the reed as a whole ultra-sensitive. If your daughter is having trouble with reeds on oboe, I suggest talking to her music teacher first, and pursuing a CF explanation second. I don't mean to rule out a CF explanation, though because like I said, my mouthpieces tend to get more residue than most.
