iTunes Smart Playlist Tip

After my decision to ditch the iPod I am still using iTunes as it is far and away the best music management software that I have seen. But I have new requirements for it - I only have 800mb of space for my daily music. The first thing to do is create smart playlist which is no problem as the image shows. However what wasn't obvious, to me at least, was how to refresh the playlist.

As long as it is flagged as live updating, all you need to do is select all of the songs in the playlist, and delete them. The playlist will immediately re-populate itself. Nice and easy.