Top: the measured skewness spectrum for each of the three frequencies. From top to bottom, 100 GHz, 143 GHz, and 217 GHz, respectively. The contributions of the dust signal and the SZ signal in the temperature maps are plotted as well. The dashed line is the resulting spectrum after subtracting the Planck dust map from the y-parameter map. The solid line is the resulting spectrum after having subtracted the frequency-corrected y-map from the temperature map. Bottom: the result of passing a Gaussian map with noise through the estimator and the result of passing the half-map difference through the estimator. For comparison, the 100 GHz skewness spectrum is plotted. Both results are consistent with a null result as would be expected.