Remove any light fixtures and ceiling vents and stuff the holes with newspaper or tape over them to prevent any water or dust from entering an electrical socket. To be safe, you’ll want to go ahead and turn off electricity running to the room altogether, and also turn off central air or heat when you start scraping so you don’t stir up the dust.
Once you get to scraping, it’s best to work in no larger than a 5-foot area at a time—otherwise parts of the surface you spray will dry before you get to it. You want to only use as much water as necessary, since too much could damage the drywall underneath.
