Clear Firefox cookies to improve computer performance and protect your privacy. Mozilla Firefox is a Web browser application that allows users to visit webpages. These websites send cookies to Firefox and Firefox in-turn saves these cookies to your computer’s hard drive. Cookies contain information about your website preferences and any personal information you may have entered into the website. Deleting cookies from Firefox will clear this personal information and free up memory on your computer.
Open the Mozilla Firefox Web browser application. Select the "Tools" menu at the top of the window.
Click "Clear Recent History" from the "Tools" home menu.
Select the time range for cookie deletion. To clear all cookies in Firefox, choose the default range labeled "Everything."
Click on the "Details" icon located underneath the time range window.
Check the box next to "Cookies." Select "Clear Now" at the bottom window to delete all stored cookies in Firefox.