How do I report a whole mailbox full of spam to Razor? SpamAssassin only handles single mail messages.

Theo Van Dinter, one of the SpamAssassin developers, has written a script which does this, along with some other reporting features. It can be picked up at

http://www.kluge.net/~felicity/random/handlespam.txt

Another simple approach (reported by Seth Arnold) is to use formail, from the procmail package:

formail -s spamassassin -r < /tmp/spam

Even simpler, why not try:

razor-report -M <mbox

I believe the method directly above will not work because SA rewrites the mail headers.