I recently acquired a 1990 Honda Civic. I have plans to fix it up. Only problem is it has 20 years of smoke stank from the previous owner.
Any ideas on how to get rid of the stench?

 

Steam clean the carpet, grab spot lifter spray and wipe down the headliner and all plastics. The buy a can of odor bomb, its a fogger you place in the car for several hours.

This is what I use

Choose any three Odor Bombs and save! Select three Odor Bomb scents of your choice for one low price. Choose different scents for different

 

+1 You can use a carpet extrator a heated one will work better grab some folex from home depo its a great spot remover also its a no rise product great for headliners also like he said a fogger would also work great too.

 

clean the interior maybe get the car ozoned but, especially change the cabin filter

 

oddly enough vanilla trees air freshners seem to help but extracted should do the trick if not new seats for you!!

 

Do a full interior shampoo/extractor be careful not to get interior to wet mayincrease smell n cause mold if it doesn't dry properly! When complete with that u can take apart dash and clean allthe build up of ash and tar in the vents andin cracksalso back of plasic pieces. When done with that put a de-ionizer in the carand run it for a few hrs after replacing cabin filter. After that ifu like u can place some liquid smell good in the I take of ac and run ac for awhile

 

The proper and only way to completely remove the smell is to burn it and throw it away! Kidding haha
Remove the interior and replace with clean one from non smoking car or replace with new!
Or remove the interior and wash it then reinstall.
Also the filter for your air system could probably also use a cleaning, then removing all your ventilation ducting and washing those out. that's one true stank magnet.