@ST: I remember from once upon a time at checkride, when I was told by my old instructor to no longer use that "trick". It will do the job i.e. with an O-200 or O-300 in older Cessnas and if you are fully aware of what you are doing, but won't in many other cases - especially younger aircraft. If you encounter carb ice, you have to apply heat asap, and yes, a bit of leaning will help increase temperature (the same lean as it is used in cold winter to heat up morning cold engines), but there is a danger in too excessive carb ice melting - resulting in engine cut off once the ice melts. The instructors I know therefore decided it is not worth the bit of more heat at increased risk.