Measure a rectangle 1 inch from the edges of the outside of your shoebox lid. Cut three sides of the rectangle, leaving one longer side uncut. If desired, score the fourth side of the rectangle on the inside of the lid, to make lifting and propping up the rectangle easy. The lid can later be positioned to best capture the sun's rays.

Line and glue aluminum foil to the inside of your shoe box, shiny side out, making sure no cardboard is exposed. If desired, add a second layer of foil. Line the inside of the lid and the flap with foil similarly (make sure the flap is lined separately and can be lifted up). The foil will reflect the sunlight and direct it to the cooking area,.

Measure and cut pieces of black construction paper to fit the inside walls and bottom of the shoebox. Glue these pieces to the aluminum foil lining. The dark color will absorb the sun's rays, increasing the interior temperature.

Measure and cut the transparent plastic to be slightly larger than the rectangle previously cut out of the lid. Tape the plastic to the inside of the lid to cover the rectangular cutout. The plastic will trap the heat inside the box. Prop the foil-lined rectangle on the lid open and hold it open using metal wire or bamboo sticks placed at the corners. Place your food, in cookware, inside the shoebox and put the lid on top. Position your solar cooker where it will get the most exposure to sunlight. Cooking time will vary depending on the food and the weather.