Clearing screen of second monitor

I have a dual-monitor display with a Nvidia GEforce 9400 video card. The login screen has a normal login on the primary display but the second display contains fragments from the previous session. I would like to clear the secondary display so that it does not display information from the previous session. This is a privacy and security issue. Any advice will be appreciated.

You could try this kubuntu solution.

Would be nice if you could post the results whether it worked or not as this has been annoying a lot of dual monitor users for quite a while now.