If you notice vapor being exerted from the top sides of the oven near the perforated holes, that is most likely steam. If you notice a vapor that is much darker and has no opacity (meaning more difficult to see through), that is most likely smoke. Sometimes food smokes when being overcooked or when a lot of oil is used. We recommend reducing the oven temperature, opening your windows, and let the fans in your oven cool the oven down. Once your oven cools down, use a warm damp cloth to clean the interior walls, ceiling, and floor.