Enter obviously bogus addresses into your blacklist with spamdb -T
peter@delilah:~$ spamdb -T -a "<wkitp98zpu.fsf@datadok.no>"
other useful options: -t enter as TRAPPED, -d delete entries
Modern spamdb does not need quote characters or < >:
peter@delilah:~$ spamdb -T -a wkitp98zpu.fsf@datadok.no