Last night we watched a show from Britain called (I think) 'War time farm' recreating what life was like for people during WW11 in Britain. One segment showed the woman of the house bringing a stew up to a boil on the little paraffin stove Then she carefully put the big pot (lid on) in a box with hay packed in it. Then covered the pot with a pillow case full of hay. After a few hours the stew was cooked. Pretty good way to save fuel back then.