This is how you clean out your PM's.
#1. at the top of the page, click 'user cp'
#2. Click 'new private messages', even if you don't have any new PM's
#3. On the right side of the screen, there's a little white box next to where it says 'Date/Time Sent' Click that box, then click the 'Delete' box below it.
#4. Now go to 'Jump to folder:' and click on 'sent items'
#5. repeat step #3
#6. Go back to 'Jump to folder:' click on '> message tracking'
#7. repeat step #3
Do this on a regular basis so we don't see "To _____" threads anymore. Thanks everyone.