Music which I've deleted from library and/or unchecked still appears on iPhone 4 and plays with checked music even after syncing. How can I delete music from iPhone so it does not play any more?
In iTunes, you can select the music to sync by track, playlist, artist, album, genre.
In order to delete a track from the iPhone, it shouldn't match any of the aforementioned criteria. Maybe the tracks are included in some smart playlist which is synced (Recent?).