Vinegar mixed with hot water at a ratio of 1 cup vinegar per gallon of water is a simple mix to try first. The vinegar has a strong scent and this mix may work best for summertime wallpaper projects when windows are open for ventilation. The fumes are not harmful but may be unpleasant in a confined area for a long period.
The mixture of liquid fabric softener and water is less diluted than the vinegar and water mix. Use 1 part liquid fabric softener to 2 parts water. The two components easily mix. Some fabric softeners include pleasant scents that make the project more pleasant.
Most wallpaper glue remover-recipes call for hot water. Keeping the mixture hot may be the bigger challenge. Mix small quantities at a time and use the mix while still hot. Place the mixtures in a microwave-safe bowl and reheat it if necessary. The hottest water that can safely be handled is the most effective.
Start by perforating the wallpaper. This process uses a specialized tool that makes small cuts through the paper allowing the removal agent better access to the glue. Apply the mixture with a sprayer or a sponge wetting the paper. After the liquid soaks into the paper for about five minutes, try scraping the wallpaper off the wall.