How to make a cozy?

I wanted to make a cozy out of an old car sun screen that wrapped around a plastic container that I can eat from. The idea of a cozy is that it insulates and keeps the heat in. So to use one and say I was having a packet of noodles that night for dinner. I would at home take the noodles of of the packet, and put into a zip lock bag, add the spices and flavour pouches to that and any other ingredients I want.
Then in camp I would place the zip lock bag into the plastic container and open it up. Then boil some water and pour into the bag. Stir a little and close the bag making sure to expel some air. Fold the bag down a little and put the lid of the container on.
After a few minutes the noodles will be cooked and ready to eat. Now while I was waiting I could be doing other camp chores or using my pot to cook another dish to go with the noodles.
The noodles will stay very hot for at least 20 minutes inside and sealed up so plenty of time to do other things and I would also use less fuel by not boiling the noodles for the three to five minutes.

Here is a photo of one I made last week. It is made from a car sun screen and is wrapped around a plastic container I will eat out of.
I just wrapped the screen around the container and cut where needed and I used some aluminum foil to hold it together.