[Dovecot] How to pull /var/mail mbox leftovers to Maildirs?

I just got my preferred postfix+dovecot(-1.1.1) configuration working on Ubuntu 8.04 server. Users and Maildirs migrated, etc.

I wasn't seeing inbound mail (in the email client) until I set:

sudo postconf -e 'home_mailbox = Maildir/'

Which I hadn't needed in the previous server's main.cf

I have a few hours worth of inbound mostly-spam in /var/mail/(username) during the time I was figuring this out.

What command line tools could I use to pull those message from the mboxes to the Maildirs?

Thanks.