Ferret smell

Friends of mine owned ferrets and their house really smelled bad. What do people use to keep the smell down?

I have never owned a ferret. My SIL owned one, but I don't remember ever smelling anything bad in her house.

I had a girlfriend that loved ferrets and rabbits. She lived in an apartment and her place smelled. She never smelled it, because she was used to it. Speaking of smells, it's extremely rare that I walk into someone's place and not smell an animal. Especially reptiles!