Like the other members have stated, fleece just seems like it would get kinda yucky pretty quick. I suppose if you are planning on changing out the fleece every single time your ball python goes to the bathroom then maybe it could work; I guess I do that with my newspaper substrate. But it just seems like if you are going to use a substrate that has to be replaced every single time your ball python uses the bathroom, then it would make the most sense to use a simple substrate that can easily be replaced, such as paper towel or newspaper. It seems like it would be a pain to have to constantly be purchasing fleece all the time when newspapers and paper towels are cheap and/or free...to be honest I'm not even sure where you would buy fleece lol.