How do you lighten wallpaper?

To lighten wallpaper, you can try a few methods depending on the type of wallpaper. For vinyl or washable wallpaper, gently scrub the surface with a mixture of water and mild dish soap, which may help to brighten the color. If the wallpaper is painted, consider using a diluted bleach solution or a commercial wallpaper cleaner, but always test a small area first to avoid damage. Additionally, replacing it with a lighter wallpaper or applying a light-colored paint over it can achieve a more permanent change.