CATS THAT SCRATCH THE FURNITURE
Your cat has destroyed the sofa with his claws, and you have reached the end of your patience. How can you live with a cat and still have upholstery?
Cats scratch to mark their territory, not to sharpen their claws. In the wild, they choose one prominent tree, reach as high as they can, and drag their claws down the trunk. This leaves visible grooves, but it also leaves a scent from the footpads. In order to prevent destructive clawing, you must provide a harmless outlet for this behavior.
Scratching posts are easily available at any pet store, but cats often fail to use them. Partly this is due to the location where we choose to put the post. To the cat, it is important that the territorial scratching post be placed in an obvious central point where it is obvious to visitors--the place where you enter the living room, for instance. (What? You already have your good couch there? Imagine that.) But if you have a little patience, you could put the scratching post in that prominent corner for a while, and when your cat develops a liking for it, you could gradually move it to a more convenient spot. Cats also like a surface upon which their claws can dig in for a nice, smooth, continuous drag, but the carpet on most scratching posts catches the claws and makes for an unsatisfying experience. In some cases, covering the carpet with a different type of fabric can increase the likelihood that the cat will use the post.
Remember that scent is as important as feel. Rubbing your own palms thoroughly along the scratch post may stimulate some cats to use the post. Catnip has also been used to impart a tempting scent to the post.
Getting your cat to use a scratching post can help a lot since this territorial scratching is usually confined to a single object. But consider the reason your cat feels the need to mark territory. Perhaps the cat feels insecure because of other stresses, particularly from other cats inside the house or increased cat activity outside of the home. Anything that helps relieve this stress will reduce your cat's need to leave his mark on your furniture.