Tin Foil
They hate to walk on it , just lay it across the top
They also make a thing called a scat mat
We tried tinfoil under our Christmas tree one year. My calico (used to climb the tree every day), curled up and slept on the tinfoil. it apparently did not bother her. Those scat mats are $$$. We tried a computer chair mat (the kind with the spikes on the bottom) upside down on the counters - they still jumped up and walked around on it - it was painful for me to step on them (I tested it), but they didn't mind at all. Stupid things.
Give me dogs any day. Cats are aggravating!!!

