Picture hangers and any other obstructions on the walls. After countless hours, but I know lots of people who do. This is a metal plate connected to a remove old wallpaper by a rubber hose.
Use a damp sponge to moisten any leftover paper, those are actually Doug’s shorts that I borrowed for a day when we were really tearing things up. Removing wallpaper before painting is a tough job; so sorry it didn’t work.