This 2 year old plugin hides on the Settings menu and let's you yank tons of old versions of posts. If you've changed your site quite a bit, but don't need to roll anything back, this might speed up your site…or at least make you feel clean. 🙂
Better Delete Revision
Remove and delete old revision of posts, pages and related meta content completely then optimize Database: reduce size and optimization to speed up!
Post imported by Google+Blog. Created By Daniel Treadwell.