Find the source first
Air fresheners only cover odors. Check under seats, seat tracks, the trunk spare-tire well and floor mats for spilled food, liquids or moisture. A musty smell often means water is leaking in from a door seal or clogged sunroof drain.
Deep clean the surfaces
Vacuum everything, shampoo fabric seats and carpets, clean the headliner gently and wipe hard surfaces. Odor-causing bacteria live in fabrics, so surface wiping alone won't fix it.
Replace the cabin air filter
A dirty cabin filter can smell like mildew every time the fan runs. It's an inexpensive part usually accessible behind the glove box.
Ozone and enzyme treatments
For smoke and strong pet odors, professionals use enzyme cleaners that break down organic matter and ozone generators that neutralize odor molecules in the air and headliner. These treatments should be done by someone experienced, with the vehicle unoccupied.
