Here are some power tips for doing things to your vBulletin database directly from the MySQL command line.

Always backup your database before editing it manually, or you'll be sorry...

Delete Guest Posts

delete from post where userid = 0;

Delete Soft Deleted Posts

delete from post where visible = 2;

Delete Soft Deleted Threads

delete from thread where visible = 2;

Delete Thread Redirects

delete from thread where open="10";