To prepare the hookah, a piece of hookah foil is placed over the top of the bowl and pressed down to make it tight. Small holes are then poked in the foil using a toothpick or a specialized tool to allow airflow. It is important to use high-quality hookah foil that is thick enough to withstand the heat from the coals, but also thin enough to allow the tobacco to heat evenly. Low-quality or thin foil can tear easily, leading to hot spots and uneven heating.