I find these shell commands quite helpful for managing email lists:

cd /var/spool/postfix/defer
cat */* | grep timed | grep -v reason | awk '{ print "UPDATE `fans`.`fans` SET `fan_email_valid` = '-1', `fan_modified` = NOW() WHERE `fans`.`fan_email` = \"" $1 "\" LIMIT 1;" }' | sed -r s/[\<\>:]//g | sort | uniq
grep -r 'No route' ./*  | awk '{print $1}' | sed -r "s/....([A-Z0-9]+).+/postsuper -d \1/g" | uniq > ../runme

Nice, huh?