Oh hear, so much pop (esp hip hop) music has indecent language on it nowadays, that it looks like your daughter may be left with very little music on her ipod. Sad. But depending upon the age of the child, I know some of it is gratuitously gross. On a positive note, you might persuade her to like the good stuff from the 60-70s.
option 1 [to delete all from ipod]
itunes/ ipod/edit/[highlight one track]select all/delete
[of course you could go thru ipod listings and highlight indivdual tracks for deletion]
If your follow option 1, you:
itunes/library [then highlight and drag tracks to ipod.
I hope this works.
If it helps, in my experience I found that children (esp girls) get bored very quickly with the gross stuff. It loses it novelty value very quickly.