On this page of the Mr Prepper guide, you will learn how to get an aluminum foil for Joe from the Junkyard to complete one of the story missions.
Joe from the Junkyard will ask you for aluminum foil – this will be your first mission from him. To get the foil, you have to go to the desert. First, repair the car using metal - it is located in the right corner of the Junkyard. Then you have to find fuel - you need at least 4 units per expedition. You will find the foil lying on the ground in one of the random locations. From a distance, it will look like a piece of cloth or paper. Collect it, go back to Joe, and give it to him.