The plate-out of radon progeny on the surface of CR-39 track detector and the walls of an aluminium can is investigated. Radium chloride solution is used as a radon source inside a can containing CR-39 nuclear track detector at the top and wall of the can. As a result, Rn daughter products will be airborne inside the can. These isotopes will quikly plated-out on the can surface and the detector. The degree of the platedout activity on the walls is estimated to be 50% in a can of radius 5 cm and height 11 cm. The effect of the electrostatic charge on the walls and the detector surfaces are also discussed.