Prepare a tortilla basket lined with a napkin or a double layer of foil that can be folded over itself. Heat a heavy, ungreased pan or comal until very hot, almost smoking. Lay a couple of tortillas in the pan, press gently for several seconds, then turn them and heat the other side. The tortillas are ready when they are soft and pliable. Stack the tortillas in the prepared basket and fold the napkin or foil, over to keep them warm and steaming while you heat the remaining tortillas.