In a well-ventilated area, preheat your iron to between 115 and 120 degrees Celsius if it has a digital readout, like Lonetto's. Otherwise, set it just above the lowest setting. "If it's smoking, it's too hot, Lonetto says. (Wax fumes aren't known to be especially noxious, but to be safe, the pros treat them as if they are. You may want to open a window.) Grab the block of wax and rub a thin layer onto the entire surface of the base. This mini-coat will protect the base material from getting scorched by initial contact with the iron. Holding the block of wax a few inches over the base of the ski, pick up the iron and hold it against the wax. When the wax begins to drip, move it up and down the base until you've left three thin trails from tip to tail.