Old rear projection TV’s use what is called a fresnel lens for their screens, and these lenses can be used to make one hell of a powerful solar cooker. Not only can these lens cook food but they can also start fire, boil water and even melt metal. What is best of all is you can find one of these lenses free, just look on Craigslist and you will find most people just give them away just to get them out of their house. So all you have to do is go pick it up and spend a few bucks on some wood for a frame and your good to go. Below are a few good videos to show you how to find one and make a frame and to see what they can do in action. I know I’ll be picking up a free rear projection TV as soon as I find one. further read...