The plastic rake is spaced in a way that it won't work with my, and my cat's, favorite litter.  Yes it's a clumping litter.  Also the tongs on the rake are very wide.  This litterbox scoops a lot of clean litter into the bin (even with the smallest clumping litter I could find).  It wastes a LOT of litter, pretty much just indiscriminately scooping everything in it's path into the bin... more of a shovel, than a rake IMO.  In order to not waste more litter than is used, I would have to dump out the bin and scoop that in order to save the wasted clean litter.... far more of a hassle than useful.