There's an old saying, "A poor craftsmen blames their tools." The saying doesn't mention that…
Removing wallpaper requires that you will need sheets of plastic drop cloths, a garden type sprayer, and a wallpaper scraper with a razor blade that can be changed when dull, or a spackle knife – AND PATIENCE. The razor scraper is best used on plaster walls, the spackle knife on drywall (or sheet rock or gypsum board.) You can use the razor edge wallpaper removal tool on drywall, but the wallpaper must be thoroughly saturated with hot water containing vinegar so it can be razored off of the drywall without damaging it. For the plastic sheets, spend a little more money for the thicker kind. Don’t use the super cheap but super thin sheets, which are hard to open from the package and will tear and will not hold the weight of the removed wallpaper lying on them when you pick them up. The sprayer has a pump handle on top. You pump this handle and build up pressure, and do it again when the original pressure has gone down. You may have seen people spraying their garden with this type of sprayer. It is perfect for saturating the wallpaper you want to remove.
Before you do anything, go to the circuit breaker or fuse box to turn off the electricity in the room where you will be removing wallpaper. Move furniture away from the walls. Place the plastic sheeting at the base of the wall, right up against the baseboard. Make sure the carpet, tile or wood floor is completely covered to prevent water damage or glue mess on floor. Make sure also that all furniture that could possibly be hit with your sprayer is covered with plastic drop cloths.
Before you even fill the sprayer, score lines on the surface of wallpaper. Be careful not to go too deep and score the walls making extra repairs necessary. There are also tools available at the hardware or paint store made specifically for breaking the surface of the wallpaper so that the water solution can get under and through the wallpaper. These tools contain small wheels with spikes sticking out.
After all of the plastic is in place and the surface of the wallpaper is scored or “Broken,” the sprayer can be filled. DO NOT buy the expensive chemicals made for wallpaper removal. They are largely ineffective and can irritate skin. If you decide to use these chemicals, make sure you are wearing the right respirator to protect your breathing paths and lungs. I strongly recommend that you do NOT use them. Regular white vinegar works better than these chemicals, and vinegar is cheap. When filling your garden sprayer with vinegar and water, use a 2:1 solution, two parts water and one part vinegar. You should use the hottest water that you can. Don’t buy or rent a wallpaper steamer. They are dangerous and it is easy to get burned. You have to stand and hold them against the wall, only covering a very small area. Wallpaper steamers do not work. Hot water and vinegar is the way to go.
Now that your spraying combination is mixed in the sprayer, pump it up and spray all the walls in the room. At first the paper will soak up all the water and the wallpaper will look dry. As long as too much water is not running onto the plastic, you can immediately go all the way around the room again with the sprayer. Then go do something else for about twenty minutes. Return to the room and spray it one more time liberally. There will be water on the plastic, and as the wallpaper is scraped off there will be sheets of paper and glue, making for a very slippery condition. Be VERY CAREFUL walking on this slippery surface
Now that the wallpaper is saturated, you can use your razor scraper or spackling knife to start removing the paper. If it is very hard to scrape the wallpaper, wait. If it is too hard to get off, you need to spray the room again and WAIT a while, and it should come off easily. The paper and glue will eventually soften up with enough spraying and time.
After you have completely stripped off the wallpaper, it is time to get the glue off. Try to remove the glue as soon as possible after removing the wallpaper while the glue is very wet. You can use a wet rag followed with a clean, dry rag or towel. Keep turning the rags as they become saturated with glue. There may be too much glue to take off, in which case you may have to use your razor scraper or spackling blade to scrape off the glue. It may be a little difficult to remove the glue, but it is not nearly as hard as stripping the wallpaper, which you have already done. Now you can roll up the sheets of plastic full of stripped wallpaper and glue.
Let the wall dry thoroughly before painting. Fans will help this happen faster. When the wall is dry, you should apply an oil base primer/sealer on it. There are some good latex primer/sealer products, but for sure shot coverage, I use an oil based product. You have to wear a respirator to use oil base primer/sealers. These respirators are not cheap, but if you apply an oil base primer/sealer without a respirator you will get sick, dizzy and high. These products can also damage the nervous system, so WEAR A RESPIRATOR. You should actually wear a respirator no matter what type of paint you are using, but they are an absolute necessity when using an oil base primer/sealer. Always make sure to read the warnings, cautions and instructions on cans of paint. As you pour the paint, make sure not to cover these warnings, cautions and instructions on the back of paint cans. These warnings are for your safety and health, as well as anyone nearby. And don’t forget about pets, they can get sick and be harmed by some products. It is best if all people and pets be somewhere else when applying products like an oil base primer/sealer. When the primer is completely dry, the repairs can be started.