How to clear history

If for any reason you wish to remove all traces of your recent browsing activity, Firefox provides a number of ways to remove any trace of it.

Press the Firefox menu button and then check under the "History" option; then select the "Clear Recent History..." option. If you're using the menu bar, check under the "Tools" menu.

After that, you'll see a new dialog named "Clear All History"'; make sure to check the "Browsing & Download History" option, and make sure that the "Time range to clear" is set to your desired interval ("Everything" will make sure that all your history is cleared).

You may also check/uncheck the other options depending of what you want to clear; for instance, clearing the "Cache" is a good idea if you don't want to leave any trace of your visit to certain websites. After you're done, click on "Clear Now", and your history will be cleared.