OS X 10.8 and later only. This script checks your entire iTunes library for missing and presumed dead tracks--those tracks that iTunes is unable to associate with a file and which are listed in iTunes with a "!"--and can create a text file listing these tracks by alleged File Path (if available), Song Name, Artist and Album, which you can view using TextEdit.
Also see Music Folder Files Not Added
To find and delete dead tracks see Super Remove Dead Tracks.
See the video on YouTube.
iTunes can't find the files pointed to by the Location property of these track entries.
Remove selected tracks and Trash or delete their files
Remove iTunes tracks disassociated from files
Display, create text file listing info of dead tracks
Create a text file containing an alphabetical list of chosen tag data
Create two playlists containing tracks with JPEG and PNG artwork
Append user-entered text to beginning or ending of selected tag of each selected track