2. Click the "Firefox" button (inverted triangle drop-down menu) and find "Options".
3. In the Options tab, find Privacy. You can set History to No History. Click Clear Recent History or Delete Personal Cookie. You can select the historical time for purging. Don't forget "OK" after your choice.
4. Delete "My Footprint" in Firefox: Click the "Firefox" button (inverted triangle drop-down menu) and find "History". Clear recent history or manage all history.
5. You can select the time range to delete the history, and then click Delete.