I have seen a very thin layer of frost removed completely from the top surface of the wing by filling the fuel tanks with relatively warm fuel. There was no moisture left at all on the wing - completely dry, so nothing to refreeze back on.
An unusual situation.
What about the tailplane, though? Well, the tail provides lift in the opposite direction (i.e. downward) on most aircraft. Therefore, a very light dusting of frost on the upper surface of the tailplane is the equivalent of the same dusting of frost under the main wing, and may therefore be acceptable, depending on the manufacturer's limitations.