Open a window and place a fan in the open space. Turn the fan on, using the highest setting available, and point it into the room to create an air current that draws clean air from outside into the room.
Go into the adjoining room and open at least one window. Leave it open to circulate the air in the room.
Close the window in the second room after approximately 30 minutes, then go into the next room and open the window in that room. The window in the first room (with the fan) must remain open at all times, with the fan running.
Leave that window open for 30 minutes, then close it, move into the next room and open the window there. Continue doing this until every room has had a chance to air out.
Turn off the fan and close the window in the original room when you're done.