Let's talk about the cat pee

Everyone knows the house we bought as the one formerly with all the cats. Each time we've been in there, the air gets clearer and clearer. BUT there is a distinct cat pee odor. We assume that sanding the floors will take care of it -- and painting AND a good scrubbing -- but worry that every now and then we might still catch a whiff. Which will seriously gross me out. Anyone know if there's anything we should do NOW, before they begin sanding etc.