Click the Firefox dropdown menu [1].
Click the Options dropdown menu [1].
Click the Options link.
Click the Privacy tab.
Click the Clear Your Recent History link [1].
Select the time range you want to clear the browsing data from by clicking on the time range drop down menu [1].
Click the Details dropdown menu.
Make sure the browsing and download history checkbox is selected [1] and click the Clear Now button [2] to clear browser data.