The method employed in the slums of post-war Birmingham was to build up a roaring fire,throw a load of salt on then hold a wet sack over the fire opening.The chimney would catch fire,darkness would descend on the neighbourhood,and also on the hearth and surrounding lino.the chimney fire would eventually burn out,the panic would subside,and after a good clean up that would be that for two or three years.Forget carbon footprints,some had'nt got shoes. :)When we were moved from the slums to a council estate some kept the coal in the baths and during the first harsh winter they were burning the internal doors to keep warm.my mates dad kept his horse in the kitchen on very cold nights.