Newspaper is super absorbent, and once they pee on it, they have a soggy mess in their box. I put newspapers on the bottom of my litter boxes to absorb the pee, and I don't bother shredding them. Then I put a 1/4" to 1/2" layer of aspen on top of the papers so my rabbits don't get so wet. After I clean the boxes, the wet papers go into the trash, and I use the aspen as mulch around my flowers. I hose down the litter after I place it around my flowers to get rid of the pee smell. The wet newspapers can also be reused as a weed block, if you are into gardening. Lay the papers down around your plants, then put the aspen on top and you block out the weeds.