A self-cleaning collecting device for cleaning a dirty gas stream including a flow-through housing having a dirty gas inlet at the base of the housing and a clean gas outlet at the top of the housing interconnected by a gas treating passage adapted to direct a gas stream vertically through the housing. As the dirty gas stream enters the housing, it is circulated through a liquid bath where noxious vapors and larger particulates are entrained in a mist of liquid droplets which are in turn captured and removed from the gas stream as it moves through a separating panel positioned above the liquid bath. As the gas flows upwardly out of the panel, the captured liquid is circulated to the liquid bath to maintain a flow of liquid within the panel which acts to continuously wash the particulates from the panel. At the same time, the gas stream continues upwardly in the treating passage where it flows through an electrostatic precipitator which removes the smaller particulates from the gases prior to their being discharged from the housing through the gas outlet at the top of the housing.