I use IE, and honestly, just
(1) closing your browser to clear any annoying session cookies
(2) deleting the permanent cookies from this site in the Cookies folder
should do the trick.
Never seen that not work. In fact, honest be said, I've never had session cookies interfere with anything (I certainly didn't bother with them cleaning up my IE for this forum, and it's all fine now).
Dunno, maybe I'm just lucky.