At the car lot I work for they will dump some fresh ground coffee on the carpets. The coffee pulls the smoke smell into it. We let them sit for a day with the coffee on the carpets then vacuum it out. I also change the cabin filter if the vehicle has one.
Sometimes I'll use a product from BG called Frigi-fresh.
BG 708
BG Frigi-Fresh®
BG Frigi-Fresh® is formulated to quickly and effectively eliminate foul, musty odors from automobile air conditioning systems. It kills mold, mildew and other odor-producing organisms that grow in the evaporator core and housing. Powerful deodorizers in BG Frigi-Fresh® keep the automobile interior smelling fresh and clean. EPA Reg. No. 44446-20-67145.
Part No. 7083
Part No. 708 Net Wt. 1 oz. (28.3 g)
Volume 1.12 fl. oz. (33.1 mL)
Net Wt. 5.5 oz. (156 g)
Volume 6.17 fl. oz. (182.6 mL)
Welcome to BG Products, Inc.
No one will buy a car off a lot that has an oder. So we always try to make them smell good.
Good luck