Try the Self-Destructing Cookies add-on, which deletes all cookies belonging to a domain a set time after you close all the last tab or window. That way they can't be built up if you leave the browser open for days or weeks and sleep the computer.
Try the Self-Destructing Cookies add-on, which deletes all cookies belonging to a domain a set time after you close all the last tab or window. That way they can't be built up if you leave the browser open for days or weeks and sleep the computer.