Incidentally, while /private/tmp is a cesspool of random detritus created by whatever process chose to abandon it there, identical daily clean-up behavior (impl

Incidentally, while /private/tmp is a cesspool of random detritus created by whatever process chose to abandon it there, identical daily clean-up behavior (implemented by /etc/periodic/daily/110.clean-tmps) can be applied to additional directories by copying the line daily_clean_tmps_dirs="/tmp" from /etc/defaults/periodic.conf to /etc/periodic.conf — create the latter if it doesn't exist, making sure it's only writable by root — and adding additional space-separated directory paths after /tmp (for a path containing a space or any other character that may be special to the shell, create a symlink to it with a clean path and add the symlink's path).