Do as Steve: suggests, then when you're finished, use a CLEAN solution of DIF by Zinsser. It can be found in any Wallpaper Retail Store or Home Center like Home Depot. I suggest you 'wash' the walls with one of those HUGH sponges you was your car with. THey're easier to handle. Don't forget to lay some plastic down first, followed by some unfolded newspaper along the bottom of the wall, to 'catch' any drippings and absorbe excess water. DO buy some 'thick' gloves because DIF loves to work with boiling hot water, literally.
Backing up a little ... WHen you use the Paper Tiger on the wall, try not to press too hard because you'll 'perforate' the wall itself. And if you do, you'll have more work of fixing the wall than you bargained for. Just press hard enough to perforate the paint and wallpaper, that's all. Again, READ the directions on the DIF 2x's at least to be sure you understand what needs to be done. The most common mistake people do is they don't use boiling hot water from a teapot AND/OR they don't let the DIF 'work' on the wall long enough. Oh, and you can never make TOO many 'perfs' in the paint/paper. The more you make, the better the DIF will work. And while you're working, be sure to have your next 'pot' of boiling water (on low) down on the stove.