Moving spam email to a different folder

The above procedure only asks SpamAssassin to examine your mail and add extra headers indicating its verdict, spam or legit. To use these headers to move junk mail to a folder called Spam in your IMAP mailbox, copy the following template to ~/.public/.forward. This is an Exim filter that looks for SpamAssassin headers that indicate spamhood. You need to create a Spam folder manually to use this. You can modify this template to save spam to other places, if you don't use IMAP or prefer another scheme. (If you already have a ~/.public/.forward file because you forward all of your mail to another account elsewhere, then you can ignore this section. You should use that e-mail provider's spam filtering services.) 

# Exim filter

logfile $home/.logs/mail/exim.log

if
    "${if def:h_X-Spam-Flag {def}{undef}}" is "def"
then
    save $home/Maildir/.Spam/
    finish
endif

SpamAssassin flags spam with a spamminess level of 5.0 or higher. You can use the X-Spam-Level: header to customize your own filter to your own liking, however. As an example, you can see NathanKennedy's .forward file on the MemberManual/Email/EximFilter page.