We steamed off some walllpaper, and most came off just fine. However, the hallway paper was attached right to the sheetrock and it appears to be a vinyl glue. The one wall that it was pasted to was painted and I'm able to slowly sand that off. But....neight GIF or TSP or sanding or.....nothing seems to work on the sheetrock walls. Aside from papering over them...any suggestions?