PLEASE do not put bleach in the urine container. It holds urine, which is ammonia based. Bleach and ammonia do not play nicely together. Instead, try vinegar. It neutralizes the ammonia in the urine and helps keep the smell down. IF you are talking about the type of composting head that separates the liquids. We put a 1/4 cup of vinegar in the liquids container of our Air Head every time we empty it. Works great! We've also not had a fly problem in the 5 years we've had our Air Head, mostly in the tropics.