screen background not clearing in standalone/web player build

I have a camera object whose position changes based on player input. In the Unity editor, this works great - there is a small screen that moves around on a black background and generally looks awesome.

The only problem is when I export to web player or standalone, for some reason the background doesn’t clear after my camera’s position changes. Instead I get a smear of camera scene that follows my screen.

Any ideas as to how to fix this? Ideally I’d like to just set some flag that causes the background to clear to black and then have my new camera scene rendered on top of it, every frame. Would adding another camera layered underneath it work, and if so, what’s the best way to get it to render black?

Try with a second camera with a clear flag “solid color”, the color being black. I guess for some reason you need the first camera to have the clear flag at depth only ?