By scratching a scratching post, a cat can get rid of loose parts of its nails. By sharpening the nails on a scratching post, a cat keeps its nails sharp. The sides that grow out then become loose and are removed with the teeth, leaving the nail with a sharp point. In nature, cats use a tree for this. With a scratching post in the house, cat owners prevent the animals from scratching furniture, wallpaper or carpet. Playful cats will soon climb into the scratching post.