How do you get rabbit urine smell out of his cage?

I have a 10 week old male rabbit and my wife keeps telling me that his urine is smelling of ammonia. I change his newspaper everyday and vacuum around his cage everyday. I also rise out his cage every other day with water and Dawn. We are getting ready to move and she says that unless I can get the ammonia smell under control, I am going to have to get rid of my rabbit. Can somebody please help??? I just got him and I don't want to have to get rid of him.