I can't remember what they were called, but we got some sticky stuff that helped protect furniture corners (Princess's favorite scratching area). It was basically clear, VERY sticky, double sided tape. Since it was clear, it wasn't very noticeable on furniture, and it also didn't ruin the furniture when removed. Princess tried clawing a few times and decided she didn't like having her paws stick to it. We were also able to remove it (for short periods of time), and she wouldn't notice it was gone. This would probably have been easier with a younger cat.
One thing not to try is aluminim foil. We read somewhere that it would prevent clawing. All it did was cause Princess to remove it, claw the couch, and then play with the foil.
Another thing not to bother with is the water spraying. That just taught her not to claw when we were in the room.
We haven't tried soft paws since the combination of the sticky material and a favorite scratching pad have worked. That would be something to try though.