To clear the web browser cache file from Mozilla Firefox follow these steps:



Source:

https://support.mozilla.org/en-US/kb/how-clear-firefox-cache 


  1. Click the menu button Fx57Menu and select Options. 

  1. Select the Privacy & Security panel. 

  1. In the Cookies and Site Data section, click Clear Data…. 

  1. Remove the check mark in front of Cookies and Site Data. 

  1. For more information about managing site data, see Manage local site storage settings. 

Fx60Cookies&SiteData-ClearCache 

  1. With Cached Web Content check marked, click the Clear button. 

  1. Close the about:preferences page. Any changes you've made will automatically be saved. 

Tip: Here's another way to clear the Firefox cache: 
Click the Library button 57 library icon , click History and click Clear Recent History…. Next to Time range to clear, choose Everything from the drop-down menu, select Cache in the items list, make sure other items you want to keep are not selected and then click the OK button. See this article for details.