My last renter smoked in the garage. I never realized this til they moved out - and apparently they did not consider it part of the house. I've actually repaintednthe walls, left it open for days but when I went back today after closing the door - it's so awful.   We cleaned behind the outlet plates and today we are going to scrub the garbage cans that were in there. Is it permanently ruined? Just curious if anyone has had to deal with this.

Paint won't do it without a shellac based primer coat first. Zinseer is what you need.

Also, don't forget the ceiling.

Rent an ozone generator.

Run it for 24 hours and it will drastically reduce the smoke smell.

@Sarah Present - make sure you bleach the garage floor. It is most likely where the ashes went.

Thank you all so much!! Great advice and will serve me well when i prepare to sell!