My ex inherited a house that a smoker, smoked every day in. This woman was awesome, completely unrelated to my ex but still gave her a house. It needed a lot of work, beyond just painting I ended up learning how to remodel from this house.
Her dad was a general contractor/site supervisor or whatever and he taught how to do things right. He didn't really help me with work, but the knowledge he bestowed was awesome.
Back to the Point
But the first thing that drove me nuts was the house smelled like smoke. Ali (my ex) told me she painted every wall, removed all the carpet, and was at a loss as to what to do next.
I ended up going down this rabbit hole and came up with some carrots I thought I'd share.
There is a machine called an Ozone Generator. Ozone, O3, generators are not "sharper image" style air filters that generate small amounts of O3. These things pump out dangerous amounts of O3. People, and pets should not be in the room when they run, or for at least double the time it has run for.
Well after hitting each room several times, 2 hours each room, then wait a few days, another run as needed. The smoke smell from decades of smoking inside was eliminated.
I ended up using this a few times on smokers cars too. (Ali smokes) and it works great but with a technique and caveat.
Most people think you want the room or car completely sealed, and to be honest you really want the machine to be fed fresh oxygen, not O3. Therefore you want to have the trunk open run the Ozone generator with a window in the front slightly cracked (to push the O3 forward), with the air/heat on and on recirculation so it pulls the O3 through the system and kills any fumes in those areas too.
I have seen some people run the machine outside the car and feed it into the car through a flex pipe to accomplish the same goal. If the car is really bad it might be another option to consider.
The links to the ozone generator are affiliate links, I may get like a fraction of a percent from any sale, but it is also the machine I use and can recommend. Don't pump it for hours in a small confined area though it will burn out the catalyst.
It was pointed out to me by Daddy Duke on the youtubes that this may also help sanitize cars of corona virus:
As always please do not defeat any car emissions systems unless the car is for racing or upgraded parts are used.