procmail installation

Hi, I've just managed to set up procmail, and it seems to work well. I have a question: while I was fiddling with it, I let incoming mail gather in the system inbox /var/spool/mail/andjoh. procmail now handles all new incoming mail, but how do I get it to process the mail already in the spool file? I can't find anything immediately obvious in the docs I'll take an RTFM as long as you tell me which M to FR Anders