It's important to be looking at these houses with a professional person who has seen a lot of houses & knows a lot about these types of things. Smells in the basement can be caused by lots of reasons: 1) Water, moisture, mildew: many houses have water leaking into the basement. There are many reasons why this happens & it's not always a deal-breaker, sometimes it can be resolved easily & sometimes it's a fatal flaw. You should not have an agent that tries to persuade you to buy every house. 2) Sometimes the carpet is dirty or has pet stains. I always recommend removing all old carpeting immediately upon moving into a house. 3) Sometimes the dryer vent is clogged or partially clogged, causing a moist lint smell. 4) Sometimes there is a lack of ventilation or air movement in the basement, causing a "stale" smell. 5) Oil furnaces & indoor oil tanks cause oily fumes. 6) Or something else. You need to be a detective to figure out what it is & how to resolve it. Or I can help you. Call me at 914-273-9688. Sincerely, Michael F. Levy, Principal Broker, Grand Lux Realty. http://www.GrandLuxRealty.com.