Something I’ve been wondering about. Deserts are kind of short in the “soft flat leaves” department. (As far as I know). (I am not an expert on deserts). There’s not a lot of water to waste pouring over your nethers, either.
Sand
There’s plenty of sand. I don’t know if it’s real life accurate, but it’s the official historical method in the Wrinkle in Time series.
Sand? Serious question. (not that I find that very comfortable, but with a lack of other resources…)
ETA: ninja’d by simulposts.
There’s plenty of sand. I don’t know if it’s real life accurate, but it’s the official historical method in the Wrinkle in Time series. This is also rumored to be one origin story for the evil that resides in the left hand.
Sandpaper?
I think sand pretty well nails it though.
If it were me, I think I’d go bare hand, then clean dirty hand with the sand. It’s hard to imagine that abrasive material rubbing against…you know.
I’d have thought getting sand there would be… unpleasant, but it’s not like I have any experience in the matter.
Wow, I’m beginning to have more sympathy for Anakin.
(BTW, not all deserts are seas of sand–some are hard solid ground. So “sand” can’t be a universal answer.)
There’s also the delicate topic of menstruating females. Maybe textiles played a role in each of these?
Perhaps tangentially, Islam apparently has a lot of rules about toilet etiquette. The Quran says you are supposed to clean yourself with water, but if water is not available you should use “earth”. Hadith sources expand on that to say you should use stones. An odd number of stones, for some reason.
Stranger
“Wipe with left hand, keep left hand off the table.”
Chopping off the right hand of a thief was the worst thing that could ever happen to him just because of that.
A smooth stone is the choice on long backpacking trips.
Yes, I had read that flat stones were the preferred means of cleaning off.
I’ve seen people in India with their little jug of water, so I imagine a small amount of water would suffice for all but food-friendly hand cleanup afterwards. That should be do-able I would think, even in a desert. Plus if dehydration is an issue, I doubt there are usually very many squidgy ones. 
One wonders if they saved their urine and used it for cleaning tasks such as this. Smelly and all that but not as bad as feces. It could also be closer to sterile than many of their water sources.