is a short cut for
LET METHOD = GAUSS
CLEAN [Gauss1 ... GaussN] [/FLUX [Min Max]] [/RESTART [File]]
Where Gauss1 to GaussN are the size scales of the Gaussian components in arcsecond. If no argument is given, these size scales are taken from variable CLEAN_SCALES if not null, or derived from the Clean beam size (0, 1 and 2 times the Clean beam size) otherwise.
Note that scale 0 (point source) is always the first scale, even if not specified as such.