Removing orphaned packages
What's the best way to remove orphaned packages on FreeBSD, i.e. dependencies of packages that have been uninstalled? I've tried pkg_rmleaves, pkg_cleanup, and pkg-orphan, but none of those three even detect orphaned packages properly. If, for instance, I install and uninstall porttools, that will leave sudo, ruby, and a bunch of other packages I don't need installed, of which pkg_rmleaves will only detect sudo.
Suppose a FreeBSD guru installs something huge, with lots of deps, and later he wants to remove it and all of its dependencies. How does he go about doing that?