Remove all trash, ash, and cigarette butts
Take out floor mats and wash them
Vacuum seats, carpets, headliner, and crevices thoroughly
Wipe down hard surfaces with an interior cleaner
Clean windows and windshield inside and out
Sprinkle baking soda on carpets and upholstery, let sit, then vacuum
Use activated charcoal or odor absorbers in the car
Place bowls of coffee grounds or white vinegar in the car overnight
Steam clean fabric seats and carpets
Shampoo upholstery and carpets
Replace the cabin air filter
Run the air system on fresh air with windows open
Use an ozone treatment if needed
Repeat cleaning until the odor is gone