This script will reset the Start and (optionally) the Stop Time of the selected tracks--or all the tracks of the selected playlist--to "0:00" and (optionally) their entire duration, respectively.
You might also be interested in Batch Trim Start or Stop Time (Seconds).
Choose to reset the tracks Start Time to 0:00 and, optionally, the Stop Time to the full duration of the track
Remove iTunes tracks disassociated from files
Re-associate batch of dead tracks with files from selected folder
Perform search-and-replace on text in your choice of tags
Convert selected tracks and export the converted files to a new folder
Edit a selection of iTunes tracks' tags "old-school"
Set year of selected tracks to their release date's year (if available)