When I got Zakura I just put a litter box in her cage and put sawdust in there, and nowhere else. (She had some hay for a "bed" but apart from that the cage was all clean) She used the litter box from day 1
(or week 7 of her life:lol: )
Sasuke I got at 3 months, and I didn't really expect him to be very well litter trained being an unneutered buck and all...but I quickly realized he would only do his business in a particular corner. So I put a litter box there...he pushed it away and weed under it:shock: Put it back, he pushed it away, tried to give him a larger box, he STILL pushed it away, put in the lower-part of the transport cage and he STILL wouldn't leave it alone.
After a while I gave up, but then he moved inside, and I tied the litter box up to the corner of the cage using a wire from a water bottle. :lol: (He had another thinner wire before but it broke) and now he uses it. He still tries to move it occasionally but I think he's finally given up.
Aroma...I tried...and failed (she had taken a liking to weeing on her pillow and my stuffed animals)...She's not neutered either but then again neither was the other two when I first got them (even up to this date only Zakura is neutered, she was 2 years then and have always used a litter box) so I don't really know what her problem is.
Now she's an outdoor rabbit so it doesn't really matter. But I plan on trying again when I get the new cages, perhaps she'll be easier once she's fully grown