How to Remove Dried Wallpaper Adhesive by Sanding

Fill a bucket with hot water and dip a rag in it. Wring out excess water and wipe the walls to soften adhesive prior to sanding. Rinse the rag often to avoid reactivating and spreading the soft adhesive.

Scrape the walls with a metal scraper to remove as much soft adhesive as possible.

Fit a sanding block with medium-grit sandpaper and sand the remaining adhesive.

Move the sanding block from place to place along the wall until the walls are free of obvious old adhesive.

Equip the sanding block with fine-grit sandpaper and sand over all wall surfaces to achieve a smoother finish and remove thin, less noticeable adhesive.