I have a house rabbit, completely free ranging. He only 'toilets' in his litter box and I have never had any smell problems. I do clean it out every day though, which I think is the way to go for a sweet smelling house and happy bunny. I use a base layer of 100% recycled paper pellets and a layer of hay on top. The pellets can be flushed, used as compost on the garden, contain no chemicals, are virtually dust free and completely control all odour. The bunny has never had any interest in eating it, though he does have a fondness for eating brown paper and cardboard when he can. I remove the hay on top daily, taking most of the urine with it and leaving the pellets to dry out then put hay on top again, usually older hay from the balcony outside, where he has a hay box. The end of litter tray with has twice daily fresh clean hay for eating, so he poops, wees one end, whilst eating clean fresh hay at other end, within easy reach. This works well in regards to him eating more hay, no odour and not too much fuss with cleaning. The whole lot gets chucked out every two or so days. With the regular daily hay clean out it works well. Cheers.