1. Focus on your Desktop.
2. ctrl+spacebar jaws should announce not selected.
3. Hit your Applications key, then up or down arrow and enter on new sub-menu.
4. down arrow and enter on shortcut.
5. type or copy in the following:

%windir%\System32\cmd /c "echo off | clip"

6. Hit Enter.
7. Now type a name. for example:

ClearClipboard

8. press enter.