Thanks for both of your replies.
It does seem a little cruel to do, not to mention REALLY expensive.
I have done the squirt bottle thing, which doesn't even faze one cat...she doesn't care if she gets wet...the other one just has to SEE the bottle and he runs away!
I buy those rectangular cardboard scratcher things that cost about $7, and they love using that, but they really like the legs of the chairs. They are kind of fancy, curved and twisty and there is one spot they just love to rip their claws into. I have filled and restained them, but the cats are just doing it again.
Oh, well.