I use paper towels. The whole bottom of my cage is covered in one layer of paper towel. Anything else and I start losing heat from my under the tank heater. Using one layer still works very good for absorbing moisture and poop poop.
I'm finding it really does not matter that much to my BPs. I'm an aspen user, and they always seem to move it around to get down to the bottom of the tank or tub. I seriously think it's in there more for me than them.
Dave
1.0 Banana Siagi (Butters) - 1.0 GHI Chocolate Het Ghost York - 1.0 Mystic Potion Sarge - 1.0 Pied Maine - 1.0 Normal Tucker - 1.0 Huffman Lopez 1.0 Black Pastel Mojave Yellow Belly Church - 1.0 VPI Axanthic Spider Ozpin- Butter Hypo Jaune