Stair rods
are making a come back.
Why Colin would you even consider removing them for cleaning purposes

(I take it this was a serious question) ,,,,, that just makes the job harder and longer.
Have you ever taken these up? You gotta remove 4 small screws (well embedded in the stair) remove fittings and rod. Then you'll have to re-fit them exactly in the same position, otherwise if they're a cheaper version your'll find one side as new the other slightly worn or discoloured :

Cover with terry towel and clean carefully around them using the spray first method. Use the vac end (no tool attached) to suck up between rod and riser (it's easier that way)

Colin, you where joking of course