Sky masks used for spectral analysis of the Planck 70, 100, and 143 GHz maps. The light blue, yellow, and red masks leave observable sky fractions f_sky of 39.7%, 59.6%, and 69.4%, respectively, and are named GAL040, GAL060, and GAL070 in the PLA. These masks are extended by exclusion of unresolved sources in the PCCS 70, 100, and 143 GHz source lists above the 5σ flux density cuts.