I'm the IT manager for a firm with about 75 employees who use Exchange Server 5.5 for email. Whenever someone left our company, I used to find reminders of their stay in the form of nondelivery reports (NDRs) for months, if not years. Whenever possible, I tried to unsubscribe the users from their mailing lists. However, as you know, many opt-out mailing lists require you to send mail from the account you want to unsubscribe. In many cases, using that account was just too much effort. I used the Rules Wizard to handle the deluge, and sometimes I recreated the mailboxes of departed staff and forwarded their mail to a custom recipient address.
Recently, though, I figured out a solution that I think works much better. When a staff member moves on to greener pastures, I delete the mailbox. For a few weeks, I personally forward the mail from friends who never got the user's "my new email address" mass mailing. Then, when the only bounced messages are from list servers and senders of unsolicited commercial email (UCE), I add the now defunct SMTP email address to my Dead Letter mailbox. Whenever I open the Microsoft Exchange Administrator program, I use the Clean Mailbox tool to purge its contents.
I considered the option of delivering all mail to an alternate recipient—a free Web account that I never check or a UCE-evaluating service such as [email protected] or [email protected] However, because some of the errant messages aren't UCE but messages from legitimate mailing lists, I don't want to take any action that might damage them.