Are you referring to your username & password for a webmail login?

*Click the (empty) input field on the web page to open the drop down list *Highlight an entry in the drop down list *Press the Delete key (on Mac: Shift+Delete) to remove it. *http://kb.mozillazine.org/Deleting_autocomplete_entries ---- * Tools > Options > Privacy > History: "Remember search and form history" *Tools > Options > Security: Passwords: "Saved Passwords" > "Show Passwords" * https://support.mozilla.com/kb/Form+autocomplete *https://support.mozilla.com/kb/make-firefox-remember-usernames-and-passwords