That's a great idea! How big are they? Is that tin-foil? Not that my advice comes from actual experience but I've been told, by many grower's, that tin-foil is bad to use. If it is wrinkled or crinkled in any way, those poits can focus the light on a fixed spot and cause burns. Not to mention, it can harbor mold behind the tin foil from the humidity getting behind it and the wall. I was told there's a product called "Panda Plastic", it has chemicals imbedded in it to keep molds away and provide adequate reflection. I'm looking for a store in my area that carries it.