If they don't want full market exposure, Sin Stocks and addictive substances (like booze, cigarettes, casinos, coffee etc) are almost always a good bet because people will spend money on them even when they shouldn't.

@Clayton Hart I don't have the answer, as the only houses I have done were minor smells, or cigarette funk.

@Mike Fletcher I agree that just because it is legal doesn't mean its a good idea for you whether cigarettes or weed but I do think having the choice is important. 

What is the best way to deal with walls that are heavily stained by cigarette smoke?

Here are the numbers:DuplexPurchase Price: 180kRent: estimated at 1k/side, 2k totalMonthly cash flow: 300 w/ property management, 500 w/o (I'm planning on managing myself)Pros: good cash flow, recently updated, good location job-wiseCons: cigarette smoke (one side is significant), both HVAC units are about 25 years old, house is located very close to major road (noisy), some roof/ceiling damage near ventsSFRPurchase Price: 180kRent: 1600 (probably high end of what I could get)Monthly cash flow: 16 w/ PM, 175 w/oPros: completely move-in ready, recently updated, good location, great neighborhood, likely higher appreciationCons: not great cash flowMy calculations are based on: 25% down payment (I'm actually planning on paying w/ cash do close sooner then do delayed financing to free up more money for investing.  

Do they give you a blindfold and cigarette first?

I pulled out the carpet out the house so there's absolutely no carpet in the house and I scrubbed the house with vinegar. unfortunately the house still smells like cigarettes and wet dog/ the pet odor smell.

I need sub floor, appliances, windows and small details, they even burned all the sinks with cigarettes. 

How many cigarettes do you, or any other adult in the household, smoke on a typical day?

Is there any way to completely remove the smell of cigarette smoke from a house, without replacing the carpet?