Hi, Try http://www.filepedia.com/desktop_software/desktop_security/ccleaner.cfm. Works with firefox. If that link does not work then go directly to their website http://www.ccleaner.com/.
i believe u dont have to download anything to clean firefox. just click (at the top) tools and then click clear private data or just press ctrl+shift+del and select what files u want to remove im not sure just trying to save u time and hd space
True firefox does have the option to clean itself but temporary files will still remain. Ccleaner deletes them both in 1 shot and the program is incredibly small.