To Delete a Pull-down Menu, Sub-menu, Command, or Separator

From the Mac OS menu bar, click Tools menu Customize Interface (CUI) or at the Command prompt, enter cui and press Enter.
In the Customize dialog box, Menus tab, Menus list, select a menu, sub-menu, command, or separator item to delete.
Click the Options action menu below the Menus list, Gear icon, and click Delete.
Note: Be careful which item is selected because you cannot undo the deletion of the item. Click Cancel to abort the changes you made.