--mbox
option in clamscan and uncomment the ScanMail
directive in clamav.conf (for clamd). All popular mail formats (Mbox,
Maildir, ...) are supported. Mail support is still under development
and may cause stability problems - if you encounter them please send
the problematic samples directly to Nigel Horne <njh*clamav.net>.
You don't need this option if you are already using some wrapper such
as AMaViS because it takes MIME decoding on its shoulders.