This was very useful for a corrupted song db in itunes:
You can use a playlist to collect dead tracks.
Create new regular playlist – Playlist1
Select whole library and drag to Playlist1
Create new Smart Playlist with the rule: Playlist is not Playlist1
Live updating checked – after you run it, uncheck live updating or you may not be able to delete tracks.
This playlist should contain all the dead tracks
Use shift-del to remove from library