The drugstore wrap requires that your foil piece be at least three times the width of your food. Fold over and roll up the edges. Then fold over and roll up the sides. This creates a sealed foil dinner to keep your food out of the coals and traps the steam which helps your foil dinner cook.
When making foil dinners, start by making a bed of coals to cook them on... this takes longer than many people think. It is recommended that you use a charcoal chimney to get the charcoal lit and covered in a light coat of ash. When the charcoal is covered in ash, it is ready to cook your foil dinners. Do not put foil dinners on if the charcoal is still black or is still on fire. This will not give you good results.
Remember to use moisture when cooking foil dinners, you can add a few ice cubes, water, soup, sauces, etc. for this purpose. If you are using a lean meat this is especially important as lean meat will turn out dry if it there is not a sufficient source of moisture.
Avoid adding cheese or any sauces that are very high in sugar content. Cheese does not turn out well when steamed and sauces with a high amount of sugar can easily burn in the foil dinner. Instead, add these after the foil dinner is cooked.
If possible, allow each person to make his or her own foil dinner. This will give them a chance to make one that they will enjoy eating.
Also, have a thick marker (such as a Sharpie) available so each person can mark their initials on their dinner. This will make sure each person receives the correct dinner after they are done cooking. If no marker is available, have the person either fold their dinner in a distinctive pattern or place it on the fire in a certain area which they need to remember. The cook should be sure to flip the dinners and place them in the exact spot if this method is used.
General guidance on cooking times is as follows:
Hamburger should be in an even layer for fully cooking the entire piece: 8-12 minutes
Potatoes should be sliced fairly thin (about 1/2 inch) or cubed in dice sized pieces for equal cooking times: 10-15 minutes
Carrots should be cut into equal pieces (about 1/2 inch): 15-20 minutes
Chicken breasts need 20-30 minutes
Hot dogs need 5-10 minutes
Whole apples need 20-30 minutes
Turn the foil packets two times when cooking. A lot of flipping is not necessary as it can puncture the foil.
Use barbecue tongs to turn the foil dinners. Barbecue tongs are longer in length to protect the cook from the heat.
Allow foil dinners to cool about 5 minutes before opening to serve. Open the packets away from your body to prevent the steam burns.
When foil dinners have been eaten, be sure all the trash gets thrown away properly. Do not throw the foil back in the fire pit as it cannot fully be burned. This leaves an unattractive campsite for the next person and can draw wildlife to your campsite.