I discovered a couple of new cat deterrents that I don't think are mentioned in any of the usual articles.
Many of these articles suggest orange peels. Well, they dry out real fast; I can't eat oranges fast enough. So, I went to the store looking for a citrus fragrance dispenser, and discovered Glade Plugins Scented Oil. I forgot the name of the fragrance; I think's it's grapefruit. Something citrus, anyway. I just buy the refill, not the dispenser. I take it apart and remove the wick. Then I pour the oil onto a cotton ball, and place on something like a margarine tub lid to protect the carpet, and place where I want the cat to stay away from. Works better than orange peels, and the room smells nice.
The other one is kind of stinky, but works good to rub on to electric cords, speaker wires, and stuff like that, because it retains its odor a long time. It's Tea Tree Oil, which I buy at the health food store. Melly just hates this stuff. I hold it up to her little nose and she recoils into the next room with her little eyes all scrunched up.
Just a couple ideas, in case you find them useful....