To uninstall unwanted toolbars added by a PDF converter, access the Tools -> Add-ons menu in your browser to remove extensions and add-ons. For Firefox users, navigate to View -> Toolbars to customize or hide toolbars. Some toolbars may require removal from the operating system, necessitating a visit to Windows settings. To temporarily run Firefox without any add-ons or toolbars, hold down the Shift key while launching the browser, which activates safe mode. Additionally, the Add-ons Manager can be utilized for permanent removal of extensions and plugins. Adjusting the menu bar visibility can also help optimize screen space.