remove music from my device in Itunes only I just want to remove all music from the my device file in Itunes. I do not want to change anything in my Iphone, just the content of the my device file.
iTunes on the computer is the 'Master' device.

Anything you discard from there will be removed from your iPhone the next time you sync it.
- unless it is purchased through the iTunes Store, allowing you to re-download directly to the iPhone at a later date.