What kind of material is best for the "towel" underneath? If it's 100% polyester ontop, would cotton be good for underneath? I'm going to a fabric shop tomorrow to get all the material and I'd like to pick the most absorbant and yet easily to clean under-bedding material. I don't want to just get bath towels because the cage for my two boys is 5x3 so it's, well, HUGE, and bath towels aren't :P I'd much rather get the right kind of material cut to size so it's easier for me... So, yes, if anyone can let me know what kind of fabric is good I'd be soooo happy!