I would not recommend this, but here is a way you could go about this...
Again I state do not do this.....
1) Identify all Terminated Uses.
2) Make sure the mailbox is disabled.
3) Remove permissions on Archive (ZAP)
4) Possibly change the Archive from a Normal Archive to a Shared Archive
5) Set the index to Failed in the Database
6) Get the Index Location from the Database on all the Indexes you have set to failed
7) From the above list write a script to go and delete the index data
--wayne