Does anyone have thoughts on metal cup cooking?

The Bushcraft folks like the idea of a billycan. That seems to be any largish tin can that they put a wire handle on. They use it to boil water and cook food. My wife and I did an overnight survival class recently from a junior college. The instructor was from the Anasazi Foundation from Larry Olsen. They only allow a metal cup for cooking and eating. This seems like a great survival setup. I have been trying different cups to see what will be useful and fit in my CamelBak. At the moment I am using a Coghlan’s 16oz Sierra Cup.

Here is the Anasazi program’s food list:
Bacon Bits
Baking Soda
Brown Sugar
Bouillon
Powdered Butter
Powdered Cheese
Cornmeal
Wheat Flour
Fruit Drink (Tang)
Lentils
Macaroni
Powdered Milk
Oats
Raisins
Rice
Salt
Sunflower Seeds
Sun-dried Tomatoes
Fresh Potato
Fresh Carrot
Fresh Onion
Fresh Apple
Fresh Garlic

We used the bacon bits, brown sugar, butter buds, flour, oats, raisins, rice, salt and sunflower seeds in our over night class.

I was curious if I could make coffee with just ground coffee and a metal cup. Here is what I did: I heated the water, pushed a neckerchief down in the water and then poured in some coffee grounds. I stirred and let it sit a little while. Then I pulled out the neckerchief. I was left with good tasting coffee with no grounds. I shook the grounds off of the neckerchief. Some stuck to it and had to be rinsed off. On our overnight trip I took along some coffee bags. They are like tea bags but have coffee in them. If you use grounds you can use any kind of coffee you like.

Has anyone tried cooking in a metal cup and what did you make?

Thanks!