You can edit your config.php and change the cookie-prefix, that will effectively force vbulletin to create all new cookies.
Although simply deleting cookies from your browser should have the same effect.
But I promise you any style issue you think you have will not be fixed by "flushing cookies."
As I PMed you please post a screenshot with exactly what doesn't look right to you, and please also try in another browser and see if the problem is across all browsers or just one.
Tried it on google chrome, msn 6, msn 8, IE6, IE7, and the same issue arises. It's really noticeable more in my vb default skin and my hmands slasher skin. I had those skinned specifically to be sleek and small and compact. So after I did all of that stuff with the database earlier today, and reuploading a copy of my vb forum folder. What was discussed in the new PM I sent you? Might be the issue. It's ALL I can think of.