You don't have to set up a cron job, you just need for the thread to check its own age when it loads.

Yes, this is the alternative way I meant. No manually selection of outdated threads, only one klick and all outdated (older than ...) threads are locked. Simply "half", ... no, better "semi automatted locking".

But maybe one or some old threads should stay open. Therefore you need further the manually selection.

Tschö, Auge