Solar cooker 2

In my science class we have been working on making and perfecting our solar cookers. In a couple of weeks we plan to have a cookout with a bunch of students, parents, and teachers. Our cooker is been good so far. The temperature is up at 160°. We need to get up in the 200° to cook better food and so it will cook faster. I think we should put a sheet of plexiglass on the top to it will keep the heat in. We do have a picture frame on top but it's not very clear so I think if it was clear it would collect and trap heat better. I think the cookout will be a lot of fun and I am excited to see all our cookers work.