It's normal for cats to scratch objects in their environment for many reasons:
Because scratching is a normal behavior, and one that cats are highly motivated to display, it's unrealistic to try to prevent them from scratching. Instead, the goal in resolving scratching problems is to redirect the scratching onto acceptable objects.
A note about scratching posts: One of the most common mistakes people make is putting the scratching post somewhere the cat doesn't want it to be. Put the post in an area that is inviting to your cat. Make sure the post is long enough for the cat to stretch to full height. If you have a larger cat, a vertical commercial scratching post might not be tall enough and you may need to make one yourself or purchase a custom one. Use a material that your cat likes...and it won't necessarily be the prettiest to us! Finally, have a variety of different scratching items such as a horizontal cardboard scratcher and a couple of different vertical posts. You have to make it easy for the cat to choose the right thing.
NO! Punishment is effective only if you catch your cat in the act of scratching unacceptable objects and have provided her with acceptable scratching objects. Punishment after the fact, won't change the behavior, may cause her to be afraid of you or the environment and may elicit defensive aggression. Used by itself, punishment won't resolve scratching problems because it doesn't teach your cat where to scratch instead.
If you do catch her in the act of scratching inappropriate objects, remote punishment is best, in which you do not directly interact with her. Ideas for remote punishment include making a loud noise (using a whistle, shaking a pop can filled with rocks or slapping the wall), throwing a pillow at her or using a water-filled squirt bottle. If punishment is interactive, she'll learn to refrain from scratching in your presence but will continue to scratch when you're not around.
To help keep them sharp, cats keep their claws retracted except when they're needed. As the claws grow too long and become curved, they can't be retracted completely. You should clip off the sharp tips of your cat's claws on all four feet every week or so. Clipping your cat's claws will also help prevent them from becoming snagged in carpets, fabrics and skin.
Before trimming your cat's claws, accustom her to having her paws handled and squeezed. You can do this by gently petting her legs and paws while giving her a treat. This will help to make it a more pleasant experience. Gradually increase the pressure so that petting becomes gentle squeezing, as you'll need to do this to extend the claw. Continue with the treats until your cat tolerates this kind of touching and restraint. It may take a little longer if she's not used to having her legs or paws handled.
Apply a small amount of pressure to her paw, with your thumb on top of her paw and your index finger underneath, until a claw is extended. You should be able to see the pink or "quick," which is a small blood vessel. Don't cut into this pink portion, as it will bleed and be painful for your cat. If you cut off just the sharp tip of the claw, the "hook," it will dull the claw and prevent extensive damage to household objects and to your skin.
There are several types of claw trimmers designed especially for pets. These are better than your own nail clipper because they won't crush the claw. Until you and your cat have become accustomed to the routine, one foot a day is enough of a challenge. Don't push to do all four at once, or you'll both have only negative memories of claw clippers!
For information on declawing your cat, see our webpage, The Truth About Declawing.