I have gotten $20 cleaning fee for small-medium amounts of sand on 2 out of the 2 claims I've filed. They know keeping your car clean is important for the next customer and they have no problem charging a shitty customer that wants to leave sand or cheetoh stains all over your seats $20 for your time. The sooner they do the sooner your picking up the next custoner anyway.
I once picked up three guys who left my backseats and floor carpeting covered with burrs. I took a bunch of pictures and then sent it in to Uber for whatever the cleaning fee would be. Then I went home, spent over 2 hours picking these things of my seats and out of the carpeting. I then get an email from Uber saying that it doesn't appear that there was enough damage to justify charging a cleaning fee. I emailed them back and told them I just spent 2 plus hours trying to clean my car and my day is shot. They emailed me back and requested that I take more pictures from different angles and they would review them again. Alot of good that does considering I just cleaned the car and can't take any more pics. Thanks for having my back Uber!