It is well documented how to add three elements to Adblock Plus for Firefox. However, I added another blocking rule to remove most of the remainder advertisements.

The three Element Hiding Rules are

facebook.com#*(social_ad)
facebook.com#*(social_ad_advert)
facebook.com#*(sponsers)

I also added:

http://www.facebook.com/ajax/emu/f.php?eid=

Which resulted in many more ads being removed.