Removing wallpaper is often tricky, and eliminating all of the glue is sometimes impossible. Most wallpaper removal projects will leave some wallpaper glue residue on the wall. The walls will often require slight repairs prior to repainting them. Still, it is essential to remove as much glue as possible and repair the walls for a professional finish. Not removing all of the glue can decrease paint adhesion and cause paint to crackle. However, removing the wallpaper is always preferred to simply painting over installed wallpaper.
Wash the walls using a hot water and soap solution to soften any remaining glue. Do not moisten the walls until damp, but lightly scrub the areas. Use a wet medium-grit sanding block to remove some of the glue grime and residue that has built up. Remember that some glue residue is okay and will be sealed by the primer.
Seal off the area using Kilz, BIN or other primer. Open the windows, and allow for ventilation prior to use. Roll the primer using a low-nap roller. Add the primer to the perimeter of the walls with an angled brush.