[nawgz]

Highly hit or miss strategy, my cat didn't care at all about foil, he even rolled around on it.

I personally recommend motion-detecting air spray cans, I didn't want the cat to feel punished by me, he just needs to be redirected. Therefore I opt for these as a deterrent, since it is both effective and an action I undertake from the cat's view. I think he hates it because of the hiss, but the air spray itself might play a role.