You can buy these translucent sticky tape strips (about 4" wide and 16" long) at a pet store. Cats hate to touch anything sticky, and won't scratch a couch/chair corner that has them on it. I just put them on the corners of my couch that my cat tried to scratch, usually they will have a favorite few corners and ignore the rest (watch them for a few days with their new furniture). They are easily replaced if you take them off, say if you were having a dinner party or something. You dont really notice them unless you are looking. Also, give the cat an alternative. I bought 4 of those cardboard scratch pads with the catnip and put them behind each piece of furniture I caught them clawing at. I clip my cat's nails too, but it just seems to make him want to scratch more.