I rigged the two lights to the top of a grill/smoker (guess I won't be smoking any ribs for a while. From the soil to the light bulb is about 3.5 feet. Since the bottom is open, I have a fan blowing up the smoker and the vent on top fully open.

What would be the best to line the inside of this smoker with? I know about whight paint, and Mylar coating, but is there anything less expensive and easier to apply and is also fireproof?