There's a script for doing bulk deletes (especially helpful because it doesn't have the broken UI problem the console has where you can't delete a machine referred-to by a task). The parameter to the script is just a regular expression on the machine names, but if you have other critera to use then you'd have to adapt the findClients() function in the script to do what you want.

Note, by the way, that if you delete a client from a console that's still running a client it re-adds itself to the default container so depending on exactly how you use the console and the volume of machines (and whether you use dynamic machine groups or hand-organized folders) it can sometimes be easier to strip the clients out in bulk, let them be re-discovered, and then refresh their inventory data so they sort into custom folders. The main reason *not* to do that would be if you use tasks with custom hand-assigned per-machine configurations instead of the normal "template" style; for those, the script will remove the machines from the tasks so their custom configs would vanish.