When you login to a web site that you want to set an Exception for, just select Never when Firefox asks you if you want to save the password for that web site.

I know the message you refer to. It pops up in a balloon in the upper left corner when you log in. I've seen it before. The problem is it doesn't always present itself. Right now it's not presenting. I've shut firefox down and loaded it again. still no balloon. Can I prompt the balloon in any other way? thanks

Tools>Options>Security - Enable Remember passwords for sites

Tools/Options/Security - enable Remember Passwords For Sites - still does not bring the balloons back. Firefox for me is going down for the count.

Are you in private browsing mode ?

I'm not sure I know what that means.

My real concern is that my that my radio router was not passworded. If someone came along, close to my house and logged in to my bank (for instance) they would have complete access to my banking records. I've since solved the problem by passwording my router and disabling the Save password function but I'm concerned mostly about the lack of control over the Firefox browser. It leads me to wonder what other control problems may exist that I should be aware of.

Try this.

about:permissions

Tools > Options > Security > Passwords: Exceptions

Include those that you do not want to save passwords for, such as those regard banks, credit cards, or other financial institutions.

To remove one already created use the "Saved Passwords" on that dialog, after supplying master password (twice if you view passwords),

Select the site and use "Remove" to remove the unwanted password.

Certainly hope you do assign a Master Password to provide some protection to your passwords.

I like that about:permissions noted by xr417, it does same as above, but allows you to modify something already in system easier. Don't think I've seen that before. Did a search on bank and found an old account/password -- don't even want an old one there.