Great combination of user name and comment.
I’ve read A Mote in God’s Eye, but not A World Out of Time, and I also remember the frictionless toilets. Perhaps Niven reused the idea.
The song “Slip Slidin’ Away” keeps running through my head.
Not mentioned so far, but every teflon coating I have seen has been dark colored – usually brown or black. I think that it would be hard to get consumers to buy a toilet with the bowl a brown or black color. Especially if they had to pay double the price for it. So consumer acceptance would work against a teflon toilet.
(Possibly teflon can be made in other colors. I’ve just never seen any.)
There is one manufactured by Gotti, Inc. It’s called The Teflon John. 
It is definitely in Mote as well, in the accomodation the Moties built for the humans. I remember the toilets in World Out of Time being a candidate for the Dictator Immortality, but not if they were frictionless.
Teflon in its natural state is pure translucent white. The only way to get it to be brown or black is to put coloring agents in it.
I strongly suspect that what you’re thinking is Teflon is actually some other non-stick surface. Some of those, tougher than Teflon (and often slightly “stickier”) are naturally of darker color.
It’s definitely in Mote, when Renner is in the palace:
Does anyone have a patent for this?
Airplane toilet bowls have been teflon coated for years. During the change from regular stainless, we at Boeing switched over from wood to nylon test turds when functional testing the lavatories. Engineering was afraid the wood turds would scratch the teflon.
Would zombies shit their brains out if they used one?
Sorry, could resist since this is DOUBLE ZOMBIE!!
“Wood turds?”
“Hairlip!”
Forget Teflon - here’s the right treatment: superhydrophobic coating.
There’s also this technology, which is a coating applied to a ketchup bottle that allows every last drop to slide out easily. Imagine a toilet bowl with the same coating. (I wonder if a shower enclosure with this coating would resist getting covered in soap scum.)
There’s not a lot of innovation in the world of toilets because there’s no money in it.
lol XD
it’s like flushing your money away.
Not to hijack, but I’m really intrigued: Were these poo dummies given any particular shapes or were they just straight cylindrical plugs? I’d assume the wood ones floated, but what about the nylon ones?
There was an entire thread not so long ago on standards for simulating turds in the plumbing industry and in other industries, with cites to quite detailed specs and photos.
Holy lack of crap.