Theodore has a very large dirt box that he usesas a litter box. It serves two purposes - he loves to dig, plus pottingsoil with compost makes a pretty good litter. It lasts quitea while. He's a dwarf and the box is about 12" x 18", so I don't evennotice it is dirty until after about a week. Then I scoop out what iswet with pee, skim most of the poops off the top, and mix some freshmix in with the remainder.
Then it just goes back into my compost pile.
I also have a box that was originally his litter box, which is linedwith old towels for him to sit in. I do a load of "bunny towels" once aweek. I used to buy the recycled newspaper litter, but it is expensive,creates a lot of waste and needs to be cleaned up quite often (I usedto clean every other day while using that stuff)
You definately don't want to let it go long enough to start seeing mold- this isn't healthy. I usually go by sight and smell - If I notice theammonia smell, I take care of it. Likewise, if it is pretty dirty orfull looking, it gets my attention. There's no hard-and-fast rule,because different bunnies "produce" at different rates.
