For a few weeks now I have been adding a few drops of pure vanilla extract (not imitation) to my rat and mouse water bottles. The difference in the odor levels is AMAZING. I was skeptical of this method, but my mom has a very sensitive nose, and I was having to clean cages every 3 days to keep her happy.

Now? A full week after cage cleaning and I can stick my head into the mouse cages (complete with male mouse) take a deep whiff, and not pass out.. in fact the rodent smell is barely noticeable! Now I have to go on visual rather than smell to decide when to clean cages.