Radiator Drain Valve

There was a few post in the automotive forums recently talking about how to open the radiator drain valve and what kind of tool was used to open it (screw driver, wrench, etc).  I have not figured that out yet, but will update this page if I find out.
 
I tried to take a picture of my valve (2001 Chevy Venture), but I could not see it because of other various components that were in the way.  So I decided to use the drawing below from the maintenance manual.