...

(I also setup two "drop boxes" for mail - say qqqspam and qqqnospam - as re-iterated below, make them difficult to "guess" as you don't want spammers filling up your spam or ham drop.)

Using procmail to

...

remove forwarding info

For MUAs (Like Netscape/Mozilla) that do a good job with keeping original headers intact, (almost) all you need to do is forward the email to the feedback account and strip off the header added by the forward. See BayesFeedbackViaForwarding for details.

Pine bouncing, for instance, adds headers like:

ReSent-Date: Wed, 27 Oct 2004 08:57:14 -0500 (CDT)
ReSent-From: My Name <myname@company.com>
ReSent-To: myname+spam@company.com
ReSent-Subject: !!! How can you refuse such a sexy plus size single community!
ReSent-Message-ID:

which may be stripped with an appropriate .procmailrc / sed stanza:

:0fw: splitmsg.lck

IMAP folders

Another option, and one that's easier for most users to use, is to set up two public IMAP folders on your IMAP server, one for MissedSpam, one for NotSpam.

...