From http://craig.backfire.ca/pages/computers/ports-clean
If you want to keep the default config, you can still quickly clean out ports with this:
find /usr/ports -type d -name work -maxdepth 3 -exec rm -r {} \;
If you have sysutils/xapply installed, you
can be even more elite with this:
find /usr/ports -type d -name work -maxdepth 3 | xapply -fP4 'rm -rf %1' -
The quickest way of cleaning ports is to give ports a separate
build directory. To do this, put the
following into the file /etc/make.conf:
WRKDIRPREFIX=/usr/obj
If that file does not exist, create it. Now, to clean ports, run the command below; it should finish in no time.
rm -rf /usr/obj/usr/ports/*
It should be noted that the WRKDIRPREFIX setting
only works on port builds started after the setting was made.
All old ports builds must be cleaned using one of the other
methods.
Special thanks to Jordan Sissel for the elite find | xapply command.
