u/AccidentalPotential3

My mom passed and we have to clean up her house to get it ready to sell. I want to try to do right by the future owners and not leave them with odor issues, because she smoked in the home for 10+ years. I've been told to paint with kills, and been told while getting quotes from professionals that we don't need to clean if we use an oil based primer? Is this true? Thank you for your input!