It is done with an "Ion generator". I have one that I used to use regularly back in the seventies..
It is a unit about the size of a battery charger. It emits an odor similar to the smell of a high voltage electric dyno.
Back in the day, I used to buy lightly burned or dead body smell cars. Remember the old tale of nothing removing dead body/corpse smells? It's a load of B S and this unit, along with a thorough cleaning with Tri-sodium phosphate (TSP), will remove all traces of odors.
The unit is heII on rubber parts. So they have to be removed/protected.
At the time I was the only one in northern Michigan with a unit. You may try an established, well equiped automotive trim shop or detail shop.