This
article[
^] talks about the cookies in Firefox. It mentioned that the cookies can be removed by removing either the
cookies.txt
(for Firefox 2 or below) or
cookies.sqlite
(for Firefox 3 and above).
Make sure that no instance of Firefox is running before trying to remove these files.
You will need to do some research on how to find out which version of Firefox is installed on the machine and where the cookies file is located.