Many remodelling or decorating projects involve removing old wallpaper from the walls in preparation of either putting on new wallpaper or painting. Although many people may have an idea of how to remove the wallpaper itself, the glue that remains after the paper is off presents its own problems. Fortunately, there is an effective method for getting it off so that you have a good surface with which to work for the next phase of your project.
Mix a solution made of 9 litres (2 gallons) hot water and 120 ml (1/2 cup) of trisodium phosphate (known as TSP) in a bucket. TSP can be found at any home improvement store.
Apply the TSP solution liberally to the areas on the walls with glue. Use a large sponge and saturate the glue. Allow the TSP to sit and work on the problem areas for 15 minutes before proceeding.
Use the abrasive side of the sponge to scrub the glue off the wall. This will take diligence and a lot of elbow grease.
Allow the walls to dry completely, leaving them to air dry overnight if possible.
Fasten some 100-grit sandpaper to a sanding block or electric palm sander and sand off any remaining glue on the wall.
Wipe the walls clean with a clean, damp rag. Allow them to air dry and the job is complete.