Martin Brinkmann, writing for Ghacks: The most recent version of Firefox Nightly, currently at version 60, comes with changes to Firefox's cookie management. Mozilla merged cookie settings with site data in the web browser which impacts how you configure and manage cookie options. If you run Firefox 59 or earlier, you can load about:preferences#privacy to manage privacy related settings in Firefox. If you set the history to "use custom settings for history" or "remember history", you get an option manage cookie settings and to remove individual cookies from Firefox. A click on the link or button opens a new browser window in which all set cookies are listed. You can use it to find set cookies, look up information, remove selected or all cookies. Mozilla engineers changed this in recent versions of Firefox 60 (currently on the Nightly channel).