Deleting the cache (temporary files) can clean up copies of old web pages. The following steps describe how to delete the cache in Firefox 87.

  1. Go to Firefox Options:

  2. On the Privacy & Security tab, select Clear Data from the Cookies and Site Data menu:

  3. Make sure Cached Web Content is selected, then click Clear. This may take a while if you have quite a few items in the cache.

  4. You may need to close your browser and re-open it once it finishes clearing the cache.