How to delete cookies on Firefox

To delete all cookies stored on your computer:

1. At the top of the Firefox window, click on the 'Firefox' button, go over to the 'History' menu and select 'Clear Recent History'.

2. Set Time range to clear to Everything.

3. Click on the arrow next to Details to expand the list of history items.

4. Select Cookies and make sure that other items you want to keep are not selected. 
Click 'Clear Now' to clear the cookies and close the Clear Recent History window.