Example: the smell that arrived with the first cold snap

The situation

Illustrative example. Not a real job or customer.

A renter moves into a freshly painted one-bedroom in an older Capitol Hill building in midsummer. Windows are open most of the time and the unit smells clean. In mid-October the building's boiler starts running. Within a few days the renter notices a stale smoke smell, strongest in the bedroom and around the radiators, and worse in the morning.

1. The renter wipes the radiator, the wall behind it and the inside of the bedroom closet with a damp white cloth. The cloth comes away tinted.
2. The renter takes photos of the cloths next to each spot, plus close-ups of the dusty gaps between radiator columns.
3. An email goes to the landlord describing when the smell started, where it is strongest and asking whether the prior resident smoked.
4. The landlord replies that the prior resident had smoked and that the unit was painted but not otherwise treated.
5. They agree on a date. The renter moves clothing and bedding out of the bedroom closet, and the landlord's contractor cleans the radiators, the walls behind them, the closet and the ceiling, then primes and repaints the closet.
6. The renter stays elsewhere for one night when a whole-room treatment is done in the bedroom, following the contractor's re-entry guidance.
7. Two weeks later, with the heat running, the renter reports a large improvement and a faint remaining note in one closet corner, which is cleaned again.

The odor resolves for the rest of the winter. The renter's move-in record is updated to note the condition and the fix, which protects the deposit at move-out.