It is necessary to prepare a heat shock for cold food. When you put anything on a cold pan and slowly heat it, the food absorbs the ointment that stays in it. When you throw on a heated pan, the food "pulls" and the grease does not suck. Try on toast, for example. It sucks oil or lard in the cold oil of the bread and the toasts are then terribly greasy. (happy) Frying pans do not tolerate heat shocks, so never warm a frying pan underwater! Never! The bottom will break out.