[CentOS] Deleting a KVM virtual machine from the command line

I am working on a sandbox machine that will allow users to play around
with building virtual machines, then blow them all away each night
with a cron job.  I wrote a small script that uses the virsh command
to destroy the VMs, then remove the storage.  For some reason the vm
name still shows up in the virt-manager GUI.  Anyone have an idea how
you delete it from there as well, without using the GUI?

thanks

Sean