If you explain the reason you want to do this you may get a more suitable answer. For instance are you looking at a privacy issue, or are you trying to find or recover something.

Firefox uses a cache, and it may be easier to use firefox's facilities to view or clear those contents. Remember you may also have files stored by FlashPlayer (Locally Stored Objects). You may have download files on your computer. And there are other files created by the OS which relate to firefox use.

See also

• Private browsing
• http://kb.mozillazine.org/Browser.cache.disk.parent_directory
• Profiles - Where Firefox stores your bookmarks, passwords and other user data (Where are my bookmarks history and other data stored)
• Downloads Window

You can find the location of the cache on the about:cache page (open that page via the location bar like a website).
Only large image and media files are stored as individual files on disk.
Other files are stored in a few large container files (_CACHE_XXX_) in the cache folder and not as separate files on disk.
The individual files on disk have random names without a file extension for security reasons: you can't open an application or start a downloaded virus inadvertently by clicking a file in the cache folder.

You can look at this extension for easier access to files in the cache.

• Cache Viewer: https://addons.mozilla.org/firefox/addon/2489

XP: C:\Documents and Settings\<user>\Local Settings\Application Data\Mozilla\Firefox\Profiles\<profile>\
VISTA: C:\Users\<user>\AppData\Local\Mozilla\Firefox\Profiles\<profile>\