Take a paintbrush or a roller ... soak the water in the water and moisten the walls with water ... don't worry, it won't do anything to the walls ....: D ..wallpaper glue with water ..so then get rid of it again with water ...: D PS; Not that you will get 1 liter of water !!! You just have to soak the wallpapers ... then take them off, it's a toy ... hercules) or other penetration that is sold into plaster, buy it in building materials (bauhaus ..Baumax, etc ..) .. the painting then holds better and is more washable, although it is Primalex which is washable .... ☢ ☠ ☣ ☠ ☣ ☠ ☢ ☠ ☢