(PET CARE) Even though it may seem like it, cats don’t claw the furniture to get revenge or because they dislike your decor. Find out why they can’t resist ripping up the couch, and how to stop your pet’s destructive clawing. — Global Animal

Humane Society of the United States
Some people think a cat’s scratching behavior is a reflection of his dislike of your favorite piece of furniture or an attempt to get even. Cats actually scratch objects in their environment for many reasons.
For instance, cats scratch to remove the dead outer layer of their claws, mark their territory by leaving both a visual mark and a scent (they have scent glands on their paws), and to stretch their bodies and flex their feet and claws.
Scratching is a normal, instinctive behavior, one that you don’t want to discourage completely. Instead, the goal is to get your cat to scratch acceptable objects (herein referred to as “posts”).
Train your cat to scratch what you want
Step 1: Watch and learn
What is an acceptable object? Certainly not the couch, carpet, or banister. Let’s look at the what, when, and how of cat scratching.
What do cats scratch? Anything with a nubby, course, or textured surface, something they can really sink their claws into.
When do they scratch? When they wake up from a nap, when they want to mark their territory, or when they’re excited about something, like you coming home from work.
How do they scratch? Some cats like to stand up against a vertical surface; others get horizontal and stick their butts up in the air for a good stretch. Some cats enjoy both angles.
Step 2: Don’t scratch here
Once you’ve figured out your cat’s preferences, you’re halfway to the finish line
- Cats are all about texture, so cover the “naughty” spots with things yours will find unappealing on her paws, like double-sided sticky tape, aluminum foil, sheets of sandpaper or a plastic carpet runner with the pointy side up.
- Many cats don’t like the odor of citrus or menthol. Try attaching cotton balls soaked in cologne or a muscle rub to the “bad” patches.
- You may have to keep these items in place until your cat is using the scratching posts consistently, which could take weeks or months. Then, remove them one at a time.
Cats just want to have fun
There are many things that can satisfy your cat’s need to scratch.
- A sturdy rope-covered upright post, a flat scratch pad of corrugated cardboard, the back side of a square of carpet, even a small log with the bark still on (be sureit hasn’t been treated with chemicalsbefore bringing it inside.)
- A scratching object can be free-standing, lie on the floor, or hang from a doorknob, whatever your cat desires. Some cats don’t care, just as long as they can scratch, so why not have a variety?
- Rub a little catnip into the post or attach a toy to the top to make it even more attractive.
- Praise your cat for using the post or any other object that is acceptable to scratch.
Step 3: Location, location, location
Put the posts where your cat wants them—next to her sleeping spot for a quick stretch after a nap, or by the front door for a really intense session after she greets you.
Put a post on each level of the house so she doesn’t have to go far to indulge.
Once your cat is regularly using her post, you can move it little by little to where you’d like it. But, really, why tempt fate? Better to leave it in her favorite spot so she leaves your favorite things alone.
Where it’s at
Scratching posts and pads are available in all shapes, sizes, and materials at pet stores, animal shelter, and on the Internet. If you’re industrious and want to make it yourself, you can find building plans online.
Stop kitty
Scolding your cat only works if you catch her scratching off-limits. If you correct her after the fact, she won’t know what she’s done wrong and could learn to be afraid of you.
- Never yell at or hit her as punishment. She may start to avoid you altogether.
- If you do catch your cat shredding a “naughty spot,” interrupt her by making a loud noise (clap your hands, shake a can of pennies or pebbles, slap the wall) and redirect her scratching to one of the acceptable items. Do this consistently to teach her “sofa bad, post good.”
Clipping claws
Indoor cats don’t wear down their claws as quickly as outdoors ones do, so they can overgrow. Untrimmed, claws can grow into the cat’s pads, leading to infection, pain, and difficulty walking and using the litter box. Check your cat’s claws every couple of weeks to see if they need to be clipped.
source: http://www.globalanimal.org/2013/05/08/how-to-protect-your-couch-from-cat-claws/40918/