[Zope] CookieCrumbler question

Hi I used the CookieCrumbler plugin the make a log in. I added the CookeCrumbler(standalone> from the ZMI , and now I have a log in form that acts oka but I want logout the user, so what I did was call the logout function of cookiecrumbler like this: <dtml-call expr="logout()"> And that does bring me to the logged_out dtml but if I push the back button and return to the logged_in and press the refresh button I still get the result as if the user is till logged in. Do I have to do anything else besides calling the logout function to make sure that the user is now back ti anonymus status?