I just tried boiling water in some foil I had in my PSK. As I unfolded the square foot of foil to make a container I found that the foil had torn at one of the creases. With the remaining 8 X 12 inch sheet I folded the foil over itself to form a dual layer container that held about 8 ounces of water. No leaks so far. I put it over a small flame from a burner on my stove and let it sit. After a few minutes I got small bubbles. A short while later the foil began to make a popping/crackling sound, but the water never came to a rumbling boil. I tried this test a second time but could not get the water to violently bubble. When I turned up the flame it just pushed up on the center of the container causing water to spill out. After my experiment I set the container aside and noticed a couple drips falling off of it. Very small, but a leak none the less. I would like to try one of those disposable baking trays that you guys have talked about. Has anyone that has boiled water in foil been able to produce large bubbles that are normally associated with boiling or am I doing something wrong?