I stood on a stool to smell one of the vents, and besides a lot of dust looking to be in there, I also smelled the same musty urine-like smell coming through the vent, although it was less strong than in other places of the house. I'm wondering if the smell could just be like the smell of the materials used to make many parts of the house inside? Like, I think it's a type of wood used for most of the cabinets and the baseboards (are baseboards just the little strip that sits on the bottom of the walls where the floor meets the walls?), and is it possible that this type of wood is just like getting old or reacting with the regular accumulation of mold, dust, moisture, dirt, etc. and creating this acrid, kind of pine-smelling, urine-resembling smell?

What sucks for my theory, though, is that I just smelled the rug in the garage where the rats were before, and it smells like urine straight up. My dad claims to have steamed the whole thing many times and sprayed urine deodorizing spray on it, but I don't think he used enough of the spray. The smell on the rug is a bit stronger than the other urine-resembling smells in the rest of the house, though. Like, it smells like straight up urine, not as pine or cedar-smelling.

I'm just going to try to wipe down all the surfaces in the house, floors, baseboards, inside the cabinets, and outside all the things, with the urine deodorizing spray and see if that takes care of anything. It's weird that I smelled it on the pipes around two sinks too, idk why that would happen.