- Stephen Harrigan, Solar Clutch, 2012 “Available material” is a major factor in making solar cookers practical around the world. Take the CooKit as an example: We assume that cardboard is readily available everywhere and cheap to obtain. However most regions of the world where they most need solar cooking you will not find cheap cardboard. You have to buy the cardboard box from a local merchant. And most likely it is torn and has holes in it that you have to patch with tape (which then you have to buy a roll of tape.) Then you have to find aluminum foil….again not easy to locate except in a “Western” supermarket. Price goes up accordingly. Glue is usually available but you have to get a whole tin of it…maybe more than you need. You will also have to buy some razor knives to cut out the ca