Get "Bitter Apple" spray at the pet store.
Harmless, natural...tastes horrendously foul, and terribly bitter (the answer to the obvious questions is...yes, I did. 'Nuff said.)
I have two VERY big dogs, who will chew their own legs if they get bored enough (nope..not kidding). They were working over windowsills, doors, shoes, cords, christmas ornaments, etc...until Bitter Apple.
Shpritz this stuff on anything you want protected. They won't forget. After a while, they'll just smell the stuff and go away.
No need to drown the cat.
Good Luck!