I’ve been testing SpamSieve for several weeks now and its getting pretty accurate. One thing keeps slipping past, email my ISP markets as spam with SPAM in the beginning of the Subject field. SpamSieve catches some but I think its due to the contents not the subject. Is there any way to force SpamSieve to catch all things marked SPAM or should I just create a filter ?
Yes, use the Filter > Add Rule command to create a blocklist rule that looks for that in the message subject.