Cats, my kitten Felis has informed me in a way which was hard to ignore, will piss in sawdust but will not shit in it.
So now I know.
To the surprise of no one who has ever heard me string more than five words together, I am not the kind of guy who can buy kitty litter in a shop. Come on.
Now I am here to tell you that normal sand works fine. Sawdust does not.