If you have been using iTunes for a while, you may have music in your iTunes music library that you don't want or need any more. Removing music you don't want is a simple thing to do. After you delete a song, delete it from any mobile device it is on as well. Otherwise, when you sync the device with iTunes, it may copy the deleted song back to the music library.
Launch iTunes on your computer. Select "Check for Updates" from the iTunes menu bar to download the most recent version of the software.
Click the "Music" option under the Library heading in the left navigation pane of iTunes.
Scroll through the music displayed in the main iTunes screen.
Right-click on any song you want to delete and select the "Delete" option from the drop-down menu. Click "Move to Trash" on the confirmation screen that pops up to permanently delete the song.
Repeat the process for any songs you wish to delete from your music library.