Abstract: A tube cleaning apparatus especially suitable for use in a hot emission stack which includes vertical cooling tubes contained within a stacked housing is disclosed herein. This apparatus utilizes a mechanical cleaning head movable vertically between a raised position and a lowered position, a support assembly for moving the cleaning head horizontally to any desired location above the tubes and an indexing mechanism outside the emission stack for indicating the horizontal position of the cleaning head. In this way, any given tube cleaned from a remote location by first moving head to a point directly above that tube and thereafter lowering the head into and through the latter.