Does work, but says it can't find the option to show unavailable videos, so you may want to enable it manually before you use this extension. Once it also glitched out and started queuing videos instead of deleting them, this was fixed by reloading the page and running the cleanup again

The only currently working tool I could find for this issue. It is P A I N F U L L Y S L O W however, any more then 500-1000 videos would take hours (based on my experience).