If it were me in my state, I would charge the tenant's deposit for any rents past due, including time it is vacant while you're fixing the mess they left, then if there was enough leftover, I would hire a cleaning crew, duct cleaning company, carpet cleaner, etc., and have them specify on bill, To Remove Smoke Residue and Smell from home., then send the tenant the itemized statement showing how their deposit was spent within the time frame required by the landlord/tenant laws.  

If they really are moving out on the last day set up a turnover of keys/walk thru that day and book a cleaner. 

If you're trying to schedule showings around Airbnb visitors, cleaners, etc. it might be a little more challenging.  

Next course of action is to use some soot cleaner to see if we can show her that is the problem. 

It is cleaner and easier to keep up with. 

We took them to small claims court with 3 subpoenaed witnesses (friend, neighbor, house cleaner) all ready to testify on our behalf that we left the house per the contract.

Run the machine empty using Finish machine cleaner (I give my tenants a couple and ask them to run it every few months).

Not every buyer will want one but some with allergies or needing cleaner air it will be a selling feature.

There are tenants with cleaner backgrounds and fewer questions than this.

Wow, my cleaner takes care of the grill when she flips the house.