carb heat. Be interested to hear why one shouldn't use it?
From the Cessna 150M, and other Cessna POH's, under "Taxiing"
The carburetor heat control knob should be pushed full in during all ground operations unless absolutely necessary. When the knob is pulled to the heat position, air entering the engine is not filtered
The design requirements require that the alternate air source not be filtered (in case of a blocked filter, which a pilot could not see during a preflight inspection)