I really wouldn't put any kind of oil on your paintwork, 'cos that and sun light will do waaaay more damage to paintwork than any moggy.... unless it's got a blow torch......

The kind of damage a cat's claw can do to a car's paintwork is about the same as grit off the road. Unless you've got a really crappy paint job. I'd ignore the cats and just keep your car clean and waxed. Your car will benifit in the long run.