I know that milar is really reflective as I have had more than one sun visor for my car made from it. I just bought a shelving unit for my plants with the floro lights and all. I was thinking about adding reflective material to the sides to keep the light at the plants and to stop from illuminating the entire room. If I can't find milar ready avail, would aluminum foil work? Also, how do you mount it to the sides of your shelves? Do you glue it to posterboard so it has some backing/support?