This thing.
The air spray duster is amazing.
- Warn. Puff in the air, say "No.",
- Worked? If not -> Puff cat, say "NO".
It took three times actually puffing the cat and now "No" is an instant "Stop what I'm doing" and when on the desk "Get in my bed" (I placed one on my desk behind the monitors where the cat would feel safe from the air spray) - Very effective, and no water mess.
Note: You shouldn't have to go further than a warn many times, but always hold the can right side up when spraying, and do not aim at the eyes or face.
A very cold liquid can come out if the can is used incorrectly, and the back of the container warns that this "can cause frostbite".