Cat's are pretty stubborn so most of them do what they want. But I have tried useing a little bit of vingar deluted with water in a spray bottle. Just spray them a lil when they are doing something bad. It's worked for me and it will not harm them in anyway. They just hate the smell.

1) "A cat will learn quickly and easily if you use the following methods: Cats don't like surprises. Squirt gun or water spray bottle - spray the cat at the time of the bad behavior. The water doesn't hurt them. It gets their attention and annoys them. Be diligent and consistent with your sprays. Loud noises - shake a can filled with coins, clap your hands, hiss, or snap, "No!", to get your cat moving in the opposite direction. Treats, pets and love work wonders. Positive reinforcement - when your cat scratches the scratching post or performs the acceptable behavior, reward them with a treat or love and affection. Most cats will learn to respond to the slightest change in the tone of your voice. Speaking to your cat in a lower, warning tone often works, before the unacceptable behavior can even happen. The face-push - push the palm of your hand gently into the cat's face to discourage biting or other undesirable behavior. Accompany it with a loud "No!"." Source and further information: http://www.meowfoundation.com/health/discipline.html 2) Further information: http://www.xmission.com/~emailbox/tips.htm http://www.sniksnak.com/cathealth/punishment.html

Lock it outside forever.

Kill it! LMAO I'm only joking! I hear that using a spray bottle with water might help...

has to be something instant like a spray bottle, or a rolled up news paper works good.

Push ups. More push ups.