Stuff…

The /var/spool/postfix/defer and /var/spool/postfix/deferred queues had gone crazy on a server and was filling up the log files with rubbish.  Needed to delete the defer and deferred queues.

postsuper -d ALL defer
postsuper -d ALL deferred

Did the trick nicely.  postsuper(1) appears to be quite helpful for this.