Searching base64 encoded text/html messages

Is there a way to search base64 encoded text/html messages for known spam
domains from within a .procmailrc recipe?

The procmail recipes you folks have guided me through are working
wonderfully well.  I believe I'm getting about 95% of the spam.  This
base64 thing looks like my last hurdle (at least for a while.)

                                - fleet -

_______________________________________________
procmail mailing list
procmail(_at_)lists(_dot_)RWTH-Aachen(_dot_)DE
http://MailMan.RWTH-Aachen.DE/mailman/listinfo/procmail