If you’re installing new wallpaper and have leftover glue, you can remove unused wallpaper paste from the bucket or pan it’s in by letting it dry. If it’s an oil-based paste, seal it in a plastic bag and throw it in the garbage. Otherwise, toss the leftover wallpaper paste in the trash. Although it’s water-soluble, don’t rinse unused wallpaper paste down the sink because it could dry in the pipes and cause a blockage.

Wallpaper in bathrooms can last anywhere from one to 10 years, depending on what type was used, how well it was installed, and the measures in place to reduce moisture and humidity levels. Opting for a more durable variety and taking all the necessary protective measures will get you closer to that longer lifespan.

While it is possible to paint over wallpaper, it is generally better to remove it first to guarantee a smooth, professional finish. Painting over wallpaper can save time, but it may lead to issues if not done correctly.

You can paint over existing wallpaper if it is in excellent condition: smooth, non-textured, clean, and firmly adhered to the wall. Ensure there are no bumps, tears, or peeling areas, and that all corners and seams are securely glued down. You might also consider painting over wallpaper if removing it would damage the underlying wall. Additionally, some wallpapers are specifically designed to be paintable, which can add texture to a room.

However, there are risks. If the wallpaper is textured, damaged, or peeling, these imperfections will show through the new paint. The moisture from the paint can also loosen the wallpaper's adhesive, causing it to bubble and potentially damage the wall. To mitigate these issues, clean the surface thoroughly and use an oil-based primer to help the paint adhere and prevent the old adhesive from bleeding through.

Hiring a professional wallpaper hanger is usually a worthwhile idea because, while the application of wallpaper itself is easy, getting the finished product to look good is complicated and takes a lot of practice and patience. A professional wallpaper hanger will not only be able to hang your wallpaper seamlessly, but they will also get an even application of wallpaper paste to avoid bubbling and imperfections immediately and over time. Plus, they can provide their professional opinion on whether to remove or wallpaper over an existing layer of wallpaper.