You might also run a SEER report of 92. It will generate a printout of stale VM boxes for your system. Stale meaning they haven't been used in over 30 days. The printout will show you how many days in the right hand column. Be sure to review the DN's carefully and make sure they are not part of some phantom forwarding system, etc., before deleting. You can also go into "Local Users", "Find" and downwards in the selection criteria, you will see a prompt for "last logged on". The highest number you can put in is 99 days. The advantage of this is that you can go right to the VM box of the resulting list and modify/delete as desired.
Roger