I just found plans to make a "Bean hole" for dutch oven cooking. Calls for digging a hole in the ground bigger around then a 55 gallon drum barrel and then line with fire bricks around the 55 gallon drum barrel that will be cut in half and placed in the ground. So I'm wondering if the firebricks hold heat longer then sandstone as I can drive around and collect sandstone for free. For those interested in cooking beans this way what you do is build a fire in the bean hole and let it burn down to coals. Then remove part of the coals and place your dutch oven with beans in the hole and cover with the rest of the coals. Place the drum lid on top of the hole and then cover with dirt. Do this early in the morning and then walk off to your hunting/fishing venture or shopping mall and when you get back home/camp you have a pot of beans ready to eat.