Put wallpaper remover in spray bottle- diluted as instructions say- score with 'Paper Tiger'- available where you buy the remover stuff. Spray walls liberally. Go away for at least a half hour- or double what the instructions say- we always go out for a meal about now. If it doesn't just peel off in huge strips, spray some more and go for a beer. It will come off easily. wash off the excess glue with water, prep for whatever you are going to put on the walls next.
Jim Ricks