According to the manpage --Yay --clean is the thought behind it, its a Yay specific shortcut for pacman -Rs $(pacman -Qqdt)Remove recursive what the Query quiet (short names) on the database lists as unrequired t
Now -Yc does not sound that bad.
It is still good to learn the verbose commands for pacman/paru/yay from the manpages, once you are familiar with them its easy to build more advanced commands for special use-cases.