Remove all trash, wet items, floor mats, and seat covers
Vacuum the entire interior, including under seats and in crevices
Find and fix the moisture source, such as leaks, clogged drains, or wet seals
Dry the car completely with open doors and windows in a dry, sunny area
Use a dehumidifier or moisture absorber inside the car
Sprinkle baking soda on carpets and upholstery, leave it for several hours, then vacuum it up
Clean affected surfaces with a vinegar and water solution
Use an upholstery or carpet cleaner designed for mildew and mold
Scrub floor mats separately and let them dry fully before reinstalling
Replace cabin air filters if they smell musty
Clean and disinfect air vents and HVAC system
Run the air conditioner and heater to help dry the interior
Use activated charcoal or odor absorbers to remove lingering smells
Repeat cleaning and drying until the odor is gone
Seek professional detailing if the smell persists