windows - How to remove leftover icons from notification area?

The notification area, when I customize it, still shows three programs and their icons. But they can not be seen if I customize to show them. They are not possible to remove from the list.
The programs are uninstalled, the registry cleaned, no leftovers there. So... how to remove these icons from the list for the tray after the programs are removed? Once again, the registry is also clean! Where are those icons/info hiding?