Section 174.615 - Cleaning cars(b) After Division 6.1 (poisonous) materials are unloaded from a rail car, that car must be thoroughly cleaned unless the car is used exclusively in the carriage of Division 6.1 (poisonous) materials.Amdt. 174-26, 41 FR 16092, Apr. 15, 1976, as amended by Amdt. 174-68, 55 FR 52684, Dec. 21, 1990; Amdt. 174-82, 61 FR 18933, Apr. 29, 1996