How to determine unused user accounts in RTC 4.x with Tomcat?

Is there a way I can extract a list of users that have no artifacts associated with them? We have a number of accounts created with wrong IDs, test accounts, etc. I need to end up with a list of users that are:

1. Already archived.
2. Have no artifacts associated with them.

Then if possible I would like to delete those users that match both criteria.

We are using Tomcat but not LDAP. I know I will need to edit the tomcat-users.xml file to remove the users, but that does not remove them from the jts database.