It seems as though extensions in Safari can't access cookies. In firefox there is a great add-on that immediately deletes cookies from a site after you close its tab. This is really helpful for viewing sites that require cookies, but that you don't want following you all over the internet.
Is there any approach I could take to mimic this behavior in Safari? I was thinking some sort of watcher on the cookie folder or linking it to /dev/null/, but I'd still like to whitelist some cookies that I don't mind keeping around and I wouldn't want to add much cpu or battery usage either.