How to Delete History in Mozilla Firefox
Most Web browsers, by default, maintain a history of your Internet browsing activity, including the sites you visit, how many times you view these pages and the exact dates when you do this. This allows a web browser to accelerate web page loading speeds and can be convenient when you don't remember a site of interest. In some cases this is something that could affect your privacy. If this is a concern, deleting your browsing history in Mozilla Firefox is straightforward and quick.
Launch Mozilla Firefox, click on the "Tools" menu, and then click on the "Clear Recent History" button. A dialog box opens up. Select the history items you wish to delete, and then click the "Clear Now" button. This procedure might differ, depending on the version of Mozilla Firefox you are using. Continue to the next Step if necessary.
Click on the "Tools" menu again and select "Options..." from the drop-down menu options. The "Options" window opens up. (Mac users should click on the "Firefox" menu and select "Preferences..." from the drop-down menu.)
Select the "Privacy" tab and click on the "Settings..." button under the "Private Data" section. The "Clear Private Data" dialog box opens up and a list of history items displays including: browsing history, download history, saved form information, cache, cookies and more.
Check (enable) the boxes that correspond to the history items you wish to delete and click "OK" to confirm. Depending on the version of Mozilla Firefox you are running, the options might display in tabs instead of check boxes. Each tab will have a specific "Clear History/Data" button.
Click on the "Tools" menu again and select "Clear Private Data" from the drop-down menu options.
Restart Mozilla Firefox.