I'm screaming at this being on apple normal iTunes support page
Follow these instructions to remove U2’s "Songs of Innocence” from your iTunes music library and iTunes purchases. Once the album has been removed from your account, it will no longer be available for you to redownload as a previous purchase. If you later decide you want the album, you will need to get it again. The album is free to everyone until October 13, 2014, and will be available for purchase after that date.