Try white vinegar......My 2 cats fight over the litter box constantly and sometimes the big one goes NEXT to the litter box....I should hang him for that but thank goodness for Clorox Wipes.....
P.S....you can be “really” firm and stick his face in it!!!!!!!
No, please don't do that to your pets. I can't believe you would even suggest such a mean thing. That's a horrible thing for you to do, and it won't change anything.