I noticed these a while ago and did a bit of digging into it. From what I was able to discover it seems the directories are used by cron to hold temporary files used when passing the output of any cron jobs to the mail subsystem (i.e. sendmail). Unfortunately for those of us who reboot daily, it tends to create one each time it is started and doesn't clean them up, which is somewhat annoying.
P.S. I put the find/delete in rc.M just before crond is started. (on reflection, rc.6 might be a better choice)
Last edited by GazL; 05-11-2011 at 04:07 PM.