I have combined the utility of Super Remove Dead Tracks and List MIAs into a single script applet and Super Remove Dead Tracks is the runner-up in this contest.
The newest version of List MIAs for the Music app will not only display information about the files no longer associated with tracks in the library, it can also delete those "dead" tracks, which is what Super Remove Dead Tracks did (and can still do if you're using iTunes).
For the purposes of illustration, I Trashed some files for this screenshot:
That column on the left displays where Music thought I last left each file; but those files don't exist anywhere because I've already emptied the Trash. Now, I can have List MIAs simply delete all or a selection of those tracks.
List MIAs is free to use in Demo Mode, during which several features will be disabled: Delete Dead Tracks from Music, Reveal Selected Track in Music, Toggle Scan at Launch and performing a scan more than once per launch are inhibited. A registration code to unlock these features is US$2.99.
More information and download is here.