I can tell you what NOT to do!!

Do not pretend to shoot the kitty with a pellet hand gun (which makes a loud POP). My Ex husband did this years ago when the cat kept climbing the tree.
One day several months later I noticed a lump under my cats skin...thinking it was something that needed to be looked at, I brought him to the vet ASAP. The Vet proceeded to cut the area and out popped a metal BB.
Yes my ex had accidently shot the cat with a pellet that must have been lodged in the gun...

Of course I then was the one left at the vets office to try and explain that one...