Lickable Wallpaper for Nurseries, or simply Lickable Wallpaper, is a kind of wallpaper with candy pictures and is an released product created by Willy Wonka. Its first appearance was in the novel, Charlie and the Chocolate Factory. Its purpose, as the name clearly states, is for licking wallpapers.
The Lickable Wallpaper is a wallpaper with various pictures of apple and grapes. When licked, the pictures taste exactly like the fruit they represent (apple, grapes)
History (contains spoilers)
Nothing is known about the origins of Lickable Wallpaper for Nurseries. Willy Wonka told the three remaining Golden Tickets winners: Veruca Salt, Mike Teavee and Charlie Bucket (not in the 2005 film) and the remaining five/three adults about the product and how it worked.
The Lickable Wallpaper may be for licking, but it is not probably for children who share the same room. Germs could easily transfer from the surface of the pictures to another tongue, causing kinds of ailments. It is possible that the candy taste on the wallpaper eventually runs dry, and more would have to be bought.