Total Annihilation is the usual suggested way to do that. There are two TA commands,one to be run on individual sims and one from City Hall's MC > Town menu to be run on the entire world -- that would be all but whichever is the currently active household. What happens if you try the Town version, do you get errors (script logs?), does MC get cranky and say "Nah, I don't wanna," does something else happen? TAing an entire world is kind of intrusive, the cursor will spin around for quite a while as all those deletions are being processed, a subsequent Save As, quit, and reload with ErrorTrap and Overwatch in place would be highly recommended to clean up any residual data, etc.