Cats are tricky creatures. They know to stay off the furniture or the kitchen counter while you’re home, but they often go where they want when you aren’t home. I heard a good way to train cats is to discretely squirt them with a water gun when they do something bad, so they’ll learn to associate the kitchen counter with getting wet and will stay off it even when you aren’t home. The Innotek SSSCAT Cat Training Tool uses a similar approach without having to spray water all over your house. It’s basically a battery-operated motion-sensor and trigger that sits on top of a can of HFC134a gas. Put the can on the surface you want the cat to stay off, and the Innotek will sound an alarm and spray the harmless gas every time the cat jumps up there. Refill cans are available, but at least one of the reviewers on Amazon said the alarm alone was enough to scare the cat away after a while. It seems the MSRP is about $65, but Amazon has it for $29.03.