How to Delete All Cookies in Firefox
Cookies are not always evil; they are frequently used by websites and web applications to ensure certain features will work properly and to simplify a number of tasks for the user (e.g. remembering your login session or UI preferences). Which means they are usually good for you, as the user. However, they are often associated with online spams and scams and also heavily used by traffic tracking and advertising networks, which are basically what earned them their bad reputation. Especially if a website or third party resources on it are creating lots of unnecessary cookies -a sign of bad web design- that's almost always an annoyance to the user which may sometimes result in privacy issues even if it won't be harmful in terms of general web or account security.
Removing all cookies might be the easiest option for many users, but there are also cases where you may need to get rid of specific cookies individually while preserving others. We covered that topic in detail in our tutorials about deleting cookies in Firefox individually and deleting cookies in Chrome individually. Now, we will focus on deleting all cookies in Firefox browser.
How to Clear Cookies in Mozilla Firefox
Let's say you have been using Firefox to access websites for a while now and you have visited hundreds of websites, used many web services, created accounts, watched videos and communicated with your friends from within the browser. The browser history has collected all the information about your online activities such as web pages you visited, resources you downloaded (images, videos, style and script files), cookies that were placed by websites and more. After visiting hundreds of websites, assuming most of them had integrations with third party websites and they displayed ads, your browser most probably has hundreds or even thousands of cookies by now. Let's delete them all, so that you can continue with a fresh and clean browsing history and no cookies.
TIP: Note that if you have always used Firefox in Private Browsing Mode, no cookies will be saved, hence there's no need for deletion.
STEP 1: Open Firefox browser and display the top menu by pressing the Alt on your keyboard (Option key on Mac).
STEP 2: On the top menu, click Tools and then click Options on the dropdown menu.
This will open the Firefox Options page. You can also open the options page by entering about:preferences into the address bar of Firefox and pressing Enter.
STEP 3: On the Options page, select Privacy from the left navigation menu.
You will now see the Privacy options page where you can control and modify options about tracking, history and location bar.
STEP 4: In the History section (this is related to your web browsing history) of the Privacy options page, click the clear your recent history link.
This will open the Clear All History dialog box. Now that you know how to open it from the Options page, you can use the keyboard shortcut Ctrl + Shift + Del to quickly open it whenever you will clear cookies or browsing history in Firefox.
STEP 5: On the Clear All History popup window, 1) select the time range to clear using the dropdown menu at the top, to delete all cookies, select Everything, 2) select which information you want to delete from the history (browsing and download history, form and search history, cookies, caches, active logins, offline website data, site preferences), to delete all data, check all items on the list, if you want to delete only the cookies, you may leave other items unchecked 3) click the Clear button.
The cookies along with other data will be deleted in a few seconds depending on the amount of data stored in Firefox. You can now start browsing websites with a clean history.
If after clearing the browser history and cookies, you are still having issues with your browser, sometimes uninstalling Firefox plugins and extensions may also be a good idea. If that doesn't help either, completely uninstalling Firefox and making a fresh install might be the ultimate solution.
Another tip that might help is that if you find cookies on your browser from websites or domains that you don't remember visiting before or you have no idea who they belong to, you can find the website owners to have a better idea about the cookies.
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