A portable grouting-cleaning machine for clad vertical walls includes a frame, an upperly open water container of essentially vertical extension supported by the frame, an endless sponge band stretched between deviation rollers positioned such to form a straight vertical sponge portion to rest against the wall to be treated, the deviation rollers having at least one motorized roller and at least one roller housed in the container, to form a loop of the band therein, two handgrips positioned side by side on the portable frame, and grippable by the operator during the machine operation, and at least one pushbutton, fixed on the frame of machine, connected into the power circuit of an electric motor which drives the motorized roller and is driven by the operator who grips the handles.