Help!! Carpet munchers!!

I need suggestions on how to stop the cats from chewing the carpet!! They've completely destroyed one section of carpet already that we had to remove and now they are onto the next one!!
I've tried that cat repellant stuff, but it doesn't work whatsoever. It stunk so bad that it repelled us more than them...they just kept eating the carpet! I'm afraid to spray anything on the carpet cause I don't want to stain it.

http://www.imagestation.com/picture/...5/fb8a746b.jpg

http://www.imagestation.com/picture/...4/fb8a74ab.jpg

Any help would be appreciated, thanks:)

My only suggestion would be to put aluminum foil over the spot. They won't chew through that, although it might just make them move on to a different spot. This is a new one for me, so I'm sorry but I don't have any more suggestions. Silly kitties, why would they eat the carpet? :)

Or do you have a rug, you could put over the spot or a stand to cover it??

I have actually bought carpet remements and rubbed catnip into them for my guys. The remements are a different colour and texture than the carpet and this is the ONLY place they are permitted to scratch/chew. By putting the catnip on it, they just LOVE those remements....