i accidently hit save password on my gmail homepage and now i cannot remove my login info. i looked under firefox settings and it does not allow me to make an exception for gmail. please help!

i hit the save password mozilla function for my gmail login page by accident. when i go under preferences, i cannot add an exception for gmail. now my login info and password are permanently displayed and i cannot undo it. the closest thing is to uncheck 'remember passwords for this site' but i do not want that because there are a lot of other sites that i want that function. when i hit 'exceptions' it has 'accounts.google.com' listed but it seems to not work for gmail and i cannot manually add an exception.