This will only work on a screen render with Regular (Normal AA) Quality anti-alias settings.
It does not work with Render to Disk.
Try making the object Positive first.
Ctrl + Left click to Select the object.
Click [A] Select Positive. Click the check mark.
Hold down Ctrl + Shift while clicking [A], continue holding down Ctrl + Shift then click check
mark again.
You have to hold Ctrl+Shift down through the whole process here if I haven't made that
point clear ; )
Left = normal
AA AA or not to AA? Right = AA off