I know a lot of people use it for uros, but there are a couple problems with it: It gets moldy pretty easily, absorbs moisture in the air, and sprouts easily too. But it is fairly digestable if it is eated in small amounts.
I think it might be OK to use in a digging box or something, but definitely not as a substrate for the whole cage.
I'm not sure about the comfortable-ness of it though, since I've never exactly tried living in it!
No, there is no way to clean it and it will mold. For those reptiles that need a substrate a soil like one is better such as cocobark or soil mix. Most reptiles that need very low humidity don't need loose substrate, those that need humidity need softer substrate that won't mold like birdseed.
The bedding that Petsmart sells for lizards is Zoo Med Excavator Burrowing Clay. I've asked about it before, and people have told me that it isn't any good. It's also expensive. The heat from the bulbs hardens it. Do you recommend Zilla substrate for lizards?
I have a digging box full of alfalfa pellets for Dudley... He LOVES it, and it makes him smell nice! He tried to eat a pellet once, but he quickly decided that it tasted nasty.
I've heard tha tit gets mouldy rather easily though, so that's the only thinkg you need to watch out for with it.
I really like non-adhesive shelf liner for substrate, and a lot of people use tile for their beardie. Right now, I use non-adhesive linoleum flooring for Dudley.