This week for its 10th anniversary, Firefox updated to version 33.1. This .1 update brings some important privacy changes that might interest you.
The big one is the "forget" button. Simply click it and choose how far back you want Firefox to forget: five minutes, two hours or 24 hours.
Firefox will close all of your open tabs, wipe your cookie and browser history for that time period and open a new Firefox window. If you forgot to start a private browsing session before doing your spouse's Christmas shopping, this is the next best thing.
If you updated Firefox and don't see the Forget button anywhere, you'll need to add it to a menu.