Lay drop cloths over the floor. If you have enough, cover the entire floor; otherwise just cover near the walls.
Score the wallpaper with a wallpaper scorer. This is an optional step to help the acetone soak into the paper, unless you have vinyl wallpaper. If you're removing vinyl wallpaper, which is waterproof, sandpaper it down to remove the vinyl coating.
Fill a spray bottle with acetone and spray it evenly across the wallpaper. Wet the paper thoroughly to ensure proper saturation. Let the acetone soak into the wallpaper for 10 to 15 minutes.
Remove the wallpaper. Start at the corners, using your wallpaper scrapping tool. If the wallpaper won't peel away, repeat step 3.
Clean the wall of acetone and paper remnants with a sponge and warm water. Clean up the dropped paper. Let the wallpaper dry before you pick it up, as acetone can cause irritation to the skin.