This is essentially a 4th tool for the Admin Tools hack I posted
here, and was written at Eva200's request.
Usage: offers mass pruning (removal) of those "Moved:" threads based on age (redirects older than X days).
Place: done in the Moderator's Control Panel
Permissions: you grant permission to moderators via their permissions page in the Administration Control Panel (under Forums & Moderators). Admins and Super Mods have permissions by default.
Perks: you can mass-delete all redirects older than x days, or select which ones to delete and which to leave.
Installation: download the attached zip file. "prune-redirects.txt" includes detailed installation instructions.
Let me know if you have any problem or need anything else added to it.