> I would like to use Spamassassin to blacklist some addresses.
> My mail reader is mutt and my MTA is exm4. I do not run a DE
> and I use fluxbox as my window manager.

Are you able to do the blocking within Exim itself (and so taking the
load off Spamassassin)?

eg in exim4.conf:

...
addresslist blocked_senders = wildlsearch;/etc/exim4/denylist
...
acl_check_rcpt:
   deny
     senders = +blocked_senders
     message = sender envelope address $sender_address is locally denied 
here.
     log_message = Blocked $sender_address on local denylist
...