Authentication handlers

[Kiran Kumar.M]

hi , i'm using mod_perl authentication handler, where the user's credentials are checked against a database  and in the database i have a flag which tells the login status (y|n), but aftr the user logs out the status is changed to n , my problem is that after logging out if the user  goes one page back and submits the browser sends the username and password again , and the status is changed to y . Is there any means of removing the username and password from the browsers cache.   Thanks in advance   Kiran