Login to the server and (as root or the account owner) run ‘mutt -f /path/to/his/mailbox’. From there you can type a capital ‘T’ (for “Tag messages matching the pattern I’m about to enter”), you will then be prompted to enter a pattern to match. Type ‘.’ (to match all strings) and enter. All messages should have an asterisk (“”) next to them.
Now type a semicolon (“;”–the semicolon tells mutt that the action you’re about to take applies to all tagged messages) and a lowercase ‘b’ (for “bounce”. Together ‘;b’ means “bounce all these messages I’ve just tagged”).
You’ll be prompted for an address to bounce the messages to. Type it in and wait a little bit for all the messages to bounce (you may be prompted by mutt to confirm you want to bounce the messages). When mutt tells you that it’s done, you can type semicolon again and then a lowercase ‘d’ (for “delete”). Type a ‘q’ to quit mutt.