Take a look at this KB article: https://support.mozilla.org/en-US/kb/password-manager-remember-delete-change-and-import You can delete your unneeded saved logins on the Preferences/Settings screen.

crocketbear said

when I go to a certain websites and log in when i click to auto log in my old log in names appear in a list I find this really annoying how can you get rid of these ??

Click the (empty) input field on the web page to open the drop-down list Then highlight an entry in the drop-down list using the cursor Down key (arrow key) (Don't click the mouse and don't press Enter) Press Shift+Delete to delete the highlighted entry (for Windows it's only Delete, but you're on Mac) Repeat till only the correct username is left.

(Hovering with the mouse no longer works)