I think I may have found a solution to "How do I clean the smell of cigarette from my used camera?" The smoke smell comes from the tar released from burning tobacco and is absorbed into the rubber and well, any surface of the camera, but especially the material that can absorb the tar. What needs to be done, as far as I can see, is we need to replace that smoke smell with something different, not try to clean the affected areas. We have to apply something that also absorbs into the rube like the the tar but smells nicer.
I have just tried my cologne, Jaguar Classic Black, Shoppers, $19.99?, on my D500 I purchased from a smoker. I also tried liquid lighter fluid, handy wipes, and white vinegar and H2O solution, but those didn't seem to penetrate well enough.
So it just came to me that my cologne smells nicer than the smoke so I sprayed some on the rubber grip area, away form the buttons, and rubbed it in with a paper towel and EUREKA! The smell was gone instantaneously. There was an overwhelming cologne scent but no smoke smell. After a couple of hours the cologne smell was hardly noticeable but the smoke smell was almost undetectable.
I've done the battery grip, lens hood (off the lens of course), sprayed the rubber grip on the lens, and scrubbed it with the paper towel and then wiped the hard parts with the damp paper towel.
It's been 5 or 6 hours since the cologne application and there is a slight scent of smoke residue, but nothing like it was at the start. Putting the camera to my eye to look through is much more pleasant now and maybe with another application of cologne, the smoke smell will disappear altogether and I imagine the cologne scent will do the same. I'm happy to share this finding will all my fellow photogs to help in everyone's enjoyment of photography.