Removing wallpaper to redecorate your interior requires a lot of time, effort, and patience. However, even when the wallpaper itself is gone, you will still have stubborn glue residue to contend with. Painting over adhesive will compromise your result, so it's best to take your time and be thorough when cleaning this up. Simple tools and procedures are all you'll need to take care of this with ease.
Step 1 - Prepare the Room
Move all of your furniture out of the room or into the center of the room away from the walls. Cover anything you can't move, as well as the floor, with drop cloths or tarps. It's also recommended that you take some painter's tape and cover all electrical outlets or simply shut power off to the room at this time.
Step 2 - Mix a Solution
There are a few solutions you can use to remove wallpaper glue and residue. Start with the simplest: hot water, liquid dish soap, and a tablespoon of baking soda. Mix these altogether in a bucket until thoroughly combined.
Step 3 - Apply the Solution to Wall
Either fill a spray bottle with this mixture to apply it or sponge it on to the glue on your walls. Let it sit for a minute or so before testing the adhesive to see if it has sufficiently softened.
Step 4 - Wipe and Scrape the Glue
Go over the glue with a rag to remove as much as possible. Then, take up a scraper or putty knife to work free anything that remains. Re-apply the solution to any resistant spots and repeat the process. Again, be thorough because any bits left behind can interfere with the look of a new coat of paint.
Step 5 - Use Alternative Methods for Tough Glue
Certain types of old wallpaper glue may prove extremely difficult to remove. For this, you can add one cup of vinegar for every gallon of water in your initial removal solution. Apply it in the same manner and wipe or scrape the softened glue away.
If the adhesive still proves stubborn, you might try a commercial wallpaper remover or a solution of Trisodium phosphate (TSP) with hot water. Since this process is very involved and more time consuming, always start by applying the removal solution to the glue to see if it will come off without further intervention.
Dispose of all the scrapings and drop cloths in trash bags and rinse the wall to get rid of any remaining removal solutions once you're finished. Make sure to let the area dry before proceeding with any new wall treatments.