Article: Click or double-click the Firefox app icon, which resembles an orange fox on a blue background. It's in the top-right corner of the window. A drop-down menu will appear. This is near the top of the drop-down menu. Doing so opens a new page in the menu. It's near the top of the drop-down menu. This option is at the top of the "History" drop-down menu. A pop-up window will appear. It's at the top of the pop-up window. Doing so prompts a drop-down menu. This is in the drop-down menu. Selecting it ensures that all of your browser's cookies will be deleted (as opposed to only cookies from a day's or a week's time). It's in the middle of the pop-up window.  You can uncheck everything else in this window, but the "Cookies" box must be checked. Any checked items will be permanently erased when you clear the cookies. This option is at the bottom of the pop-up window. Your Firefox cookies will be cleared. It may take a few minutes for Firefox to finish clearing your cookies. If you don't want Firefox to store cookies, you can disable them by doing the following:  Click ☰. Click Options (on a Mac, click Preferences). Click the Privacy & Security tab. Scroll down and select to the "Custom" option near the top of the page. Check the "Cookies" box. Select "All Cookies (will cause websites to break)" option.

What is a summary?
Open Firefox. Click ☰. Click Library. Click History. Click Clear Recent History…. Click the "Time range to clear" drop-down box. Click Everything. Check the "Cookies" box. Click Clear Now. Prevent cookies from appearing in the future.