Strip old wallpaper down to bare wall by scoring, soaking, and scraping without gouging the drywall underneath.
Turn off power to the room at the breaker (you will be working with water near outlets), then cover outlets and switches with painter's tape. Lay drop cloths or old towels along the baseboards to catch drips and peeled paper.
Lift a corner with a putty knife and try peeling the paper dry — strippable wallpaper may come off in sheets. For the backing or stubborn paper, run a scoring tool (like a PaperTiger) over the surface in circles to perforate it so liquid can reach the adhesive.
Mix hot water with a wallpaper-stripping solution (or a splash of fabric softener or vinegar) and apply generously with a sponge, spray bottle, or garden sprayer. Let it soak in for 10–15 minutes so the adhesive dissolves. Work one section at a time so it does not dry out.
Use a wide plastic or metal putty knife held at a low angle to scrape the softened paper and paste off the wall. Hold the blade flat to avoid gouging the drywall. Re-soak any spots that resist rather than forcing them.
Wipe the wall with warm soapy water to remove all remaining adhesive — leftover paste will telegraph through new paint or paper and feel sticky. Let the wall dry fully before priming or painting.