Carb Icing: Don't forget that if it is VERY cold the chances of carb icing are actually REDUCED, as the temperature drop across the venturi is sufficient to take already cold air BELOW the temperature at which ice will form. In fact, by using carb heat you could actually warm the air to the point where ice CAN form and you then have no way of removing it.
Airframe Icing: Beware of flying in cold clear air and then maybe descending into cloud which is above freezing. With your cold-soaked airframe you will accumulate ice.