I've run into this before, so I'll be following to see if you come across a better answer. That said, the one sure fire way to cut the connections is to reboot the PBX. It seems unlikely to me that you'd have 10 real connections, so there's a very good chance you've got some old connections that aren't real.
Hopefully somebody will be able to give you a better way to identify and kill them. Of course, if you're running the PBX at a business that closes overnight so there's no real problem with rebooting, I'd just schedule a reboot for tonight and be done with it.