remove all ports

[Dino Vliet]

Hi freebsd people,
just to make sure I don't end up with a unworkable system I want to ask the list if I'm on the right track.

I have this workstation running FreeBSD 8.1 and have used it as an application/database server for most of the last 2 years. Do to my assignment being finished I want to rearrange stuff, without going to a re-install as everything has been setup to my liking (gmirror etc etc).

Over time a few ports  were installed, for which I have no use now. I figured out the alternatives I have are:

A) remove all ports Except the ones I would like to keep
B) remove all ports and then
 reinstall the ports that I would like to keep

What are the commands for option A en B (assuming bash, weka, postgresql*, screen, gawk, rsync, jdk would have to
 stay?)

For option A I tried pkg_deinstall -r xorg-minimal-7.5.1 but only that port got removed and not the ports I found after I did pkg_info -r xorg-minimal-7.5.1

Brgds
Dino