How to Take Off Wallpaper from Drywall by Soaking and Scraping
Once the wallpaper is removed, wash the walls with a wallpaper removal solution. Rinse the walls thoroughly.
Wash off any remaining adhesive residue with removal solution or with a nonphosphate cleaner in water, using a large sponge or sponge mop.
Warning: You can use an abrasive pad or steel wool to help you remove the adhesive residue on plaster, but be careful on drywall. Avoid overwetting or abrading the paper facing.
Rinse your sponge often in a separate bucket of water, squeeze it out, and continue rinsing your walls until all the residue and remover solution are gone.