Java Programming

In my application I display a JSF page where the user can enter selection values which are then used to retrieve the records from the database. The information retrieved is stored in a bean and then displayed as a DataTable. This works OK.
The page contains a "Cancel" button which removes the bean from the session scope. The next time the user starts the page, it is empty again. This works OK as well.
If the user uses the browser's back button the previous page is displayed but if he starts the page again, the already existing data from the bean are displayed respectively the page looks exactly as it was before using the back button. I would like it to be empty as well (initialized).
I cleared the cache using the response.setHeader() statements within the JSP. The page isn't cached anylonger but it still shows the old data.

Is there a way how to force JSF to initialize the page ?

thanks