Firefox keeps a copy of certain elements on the web pages you visit, such as images, to load pages faster the next time you view them. In Firefox, it’s very simple to clear the cache. Here’s how you can clear Firefox’s cache in 2 easy steps:
In the upper left corner, click on Firefox orange button. Then History ---> Clear Recent History.
Choose Everything from the time range drop down. And make sure Cache is checked. Uncheck all other options. Finally, click on Clear Now.
Voila! Your browser’s cache is now cleared!