I like this decades-old myth that cats prefer cleaner smelling litter. They don't. True, if you let litter get insanely dirty they won't want to poop there anymore, but if the litter literally didn't smell like cat shit and piss the cats would be very confused and probably start shitting somewhere else. Cats are kind of dumb that way and have to be constantly reminded in some way that, yes, this is the bathroom.