- Press CTRL+Shift+Delete. You will see this window:
- Check the boxes next to Cookies and Cache, as shown in the picture above.
- Press the Clear Now button at the bottom of the window.
- Close the window, then close and restart Firefox.
If you also have a problem with logging in or out of certain websites, you can repeat these steps and check the Active Logins box, then click Clear Now again. This will require you to log back into any accounts that you've set to "remember" your login information.