How to clear a browser's cache?

Why are we still "logged in" to Quora in other browsers, and why doesn't clearing cookies/cache and restarting my computer clear the sessions?

• I've long since restarted my laptop, cleared cookies and the cache.  Who else finds this disturbing?

• Answer:

  Because the system needs you to tell it positively that you have left. The action of clearing the cookies only clears cookies, so the Quora site can no longer identify your browser. It doesn't send any signal to the Quora site that you have left, neither does simply closing the browser window or tab. Next time you visit you'll have to log in again, and start a new session because the site won't recognise you -- the cookie has gone. Logging in doesn't automatically close your earlier session. To formally logout, use the Logout link at the bottom of the drop-down menu in the Quora toolbar, under your name. Click. Then, when you get to the post-logout page, observe the notice reminding you that you haven't logged-out from earlier sessions. (Probably you just closed the tab, or navigated away from Quora without actually logging out.) Click on that 'Logout from all browsers' (or whatever it says.) You'll get a confirmation.