In the early 70's, I was a Citroen dealer. Some of the older Cit's had no heaters,s they were an option in that period. Once, I borrowed one to run up to Maine for Christmas. This was an extremely clapped out car. Even though it ran, it was not worth retrofitting with a heater. Along the road, I picked up a hitchhiker, a construction worker also headed for Maine to visit his family for the holidays. He had been working in Tennessee. When we got to talking, he mentioned that he had some very fine 'corn' with him and, as there was not heater, we had to provide our own heat. It was truly "smooth" and, even though the temperature was well below freezing, it kept us warm. In fact, it kept me warm all the way to my friends' place. Of course, I would never do such a thing today [it says here].