I used to get a cat that would sleep on the hood of my car coz it has that hood scoop. On cold nights, the hood scoop would let the hot air escape from the engine bay and the cat would sleep next to it for warmth.
Man, the scratches on my hood and the tell tale foot prints the next morning would have me boiling mad! So I got some red pepper powder and sprinkled it on the hood the next night. Why? Coz cats like to lick their paws. Sure enough, there were foot prints again the next day.

However, that was the last time I saw any prints.

I taught that cat a lesson!