Join Date: Mar 2010
Location: Ontario, Canada
When I first adopted my girls, I put them each in a safe room and the safe room had no furniture that was likely to be scratched (no couches, etc.). I then played with them around their scratching posts...dangling toys above or around the posts and so forth. Once I moved the girls out of their safe rooms, I brought the scratch pads and mats with me and they continued to use those rather than my furniture. Catnip is also a good idea, as Digikid suggested.
If it's possible to ask the former foster Mom what kind of post/mat she used, then I would do so. Otherwise, you'll have to experiment with posts and mats made of different materials, etc. Given that cats like to both stretch and scratch, a tall scratch post (twice the cat's length) is a good investment.
I would try to put a scratch mat/post close to where she sleeps, because stretching and scratching is something cats like to do when they first wake up. I would also try to put something over any furniture that she's currently scratching (what you might use depends on what she's scratching). When cats scratch, they leave both visual and scent markings behind, and those markings attract them back to the same spot over and over. So, covering up the markings so as not to keep attracting her back there would be a good move. You can also try spraying the furniture with a scent cats don't like (such as lemon air freshener). Alternatively, limit her access to those rooms where she's scratching furniture until she gets accustomed to using her scratch posts. Once she starts depositing her scent/visual markings on the scratch posts, she'll return to them rather than your furniture.