Dry cleaning methods are safest for cleaning any kind of wallpaper, whether it’s made of paper, fabric, vinyl or some combination of the three. Regular vacuuming or cleaning with a dry sponge or soft cloth is vital on a regular basis thanks to static electricity that will attract dust and dirt to the walls over time.
When vacuuming or cleaning with dry wiping isn’t effective, consult the care instruction sheet packed with the wallpaper rolls. “Washable” wallpaper, usually a combination of vinyl and paper, may be washed, but not very often. If the instructions specify that the paper is “scrubbable,” it’s probably made of vinyl, so you may wash the wall more often following the manufacturer's instructions. It’s best to vacuum or dry-wipe washable wallpaper to control dirt, then wash the wall only when it becomes absolutely necessary.
If care instructions can’t be found, you’ll need to test the cleaner you intend to use in an inconspicuous spot to guard against streaking, fading or staining. Use a wallpaper remnant if you have one. Otherwise, choose a location on the wall behind furniture for the test site.
Regardless of the type of wallpaper, don’t use anything more abrasive than a clean, plain sponge, and don’t clean with anything harsher than water with a very small amount of mild detergent like a clear hand dishwashing liquid. Colored cleaners may leave splotches or stains behind. Don’t use scrubbing pads or brushes of any kind, gritty cleansers, chlorine bleach, harsh alkaline solutions or solvents such as spot removers.
If your wallpaper won’t stand up to washing with a water-and-detergent solution — and many paper and fabric wallpapers can’t — wallpaper supply stores sell a pliable, clay-like cleaning product that will absorb soils from the walls. Be sure to read product instructions carefully and test the cleaner in an inconspicuous location before proceeding. If you use such a product, carefully monitor effectiveness as you clean and discard pieces that have absorbed soil to capacity. Continue cleaning with a new chunk of unused cleaner if necessary. Small bits of this material may be left behind when you’re done, but may be safely removed by brushing or vacuuming.
Use two buckets to clean wallpaper with a cleaning solution as above — one for the cleaning solution, the other filled with clean, warm water for rinsing. Clean one section at a time and work from the bottom up, wiping in the same direction as the seams (which are usually vertical). Cleaning from top to bottom may cause water to drip down the wall; the resulting streaks will be very difficult if not impossible to remove. Wiping a wet sponge across seams can force moisture under the paper and weaken the glue’s bond. Gently pat each cleaned section dry with a soft, clean terry-cloth towel.
This cleaning advice applies only to common soil and stains. Wallpaper that has become mildewed or infested with mold cannot be cleaned effectively. It must be removed completely and replaced, if desired. Once apparent on the wall, mold likely will have penetrated the paper, glue and perhaps even the drywall underneath. Once the wallpaper and glue have been removed, the underlying wall may be cleaned with a solution of water and chlorine bleach or borax to kill and remove mold or mildew. Use one cleaner or the other — never mix chemicals together in an attempt to boost effectiveness. Rinse the cleaning solution thoroughly with clean water and allow the wall to dry completely before preparing it for painting or re-papering. Steam vapor cleaners, used properly, may also be effective for wall washing and mold removal.