Place a black pot on top of a square cake rack, placed inside a plastic baking bag. A standard size rack in the U.S. is 25 cm. (10 in.). This is placed inside the funnel, so that the rack rests on the top edges of the bucket or wastebasket. Since the sunshade material is soft and flexible, the rack is necessary to support the pot. It also allows the suns rays to shine down under the pot and reflect on all sides. If such a rack is not available, a wire frame could be made to work as well. Note: The flexible material will squash down around the sides of the rack.