Turn off power to the room and remove all furniture and accessories. Lay heavy plastic on the floors so that the plastic extends up the walls a few feet. Hang plastic sheets down the walls for protection. Run one long, continuous strip of tape along the top of each wall near the ceiling; secure the plastic sheets along the strip of tape.
Lay rosin paper on the floor over top of the plastic to give yourself traction as you remove the stipple.
Place a dust mask over your face and goggles over your eyes. Start in the corner with a small section, and saturate the stipple with a typical garden sprayer.
Scrape off the stipple with a wide putty knife until the section is smooth. Move on to an adjoining section, and continue in that fashion for the whole ceiling.
Pull the plastic from the walls and fold all the stipple and wall plastic up in the plastic sheets from the floor; remove the stipple and plastic from the house.