The invention relates to an apparatus (70) and method for removing particles from an interior of a CRT envelope (12). The CRT envelope includes a faceplate panel (14), with a color selection electrode assembly (30) detachably mounted therein, sealed to a funnel (18). The apparatus comprises a plurality of thumper mechanisms (84, 184 and 284) for imparting asynchronous vibrations to the funnel of the envelope while the interior of the funnel is flushed with a suitable fluid. The embodiment further includes a plurality of vibrators (51) for imparting asynchronous vibrations to the color selection electrode assembly to remove particles therefrom, before the color selection electrode assembly is mounted into the panel and sealed to the funnel. A method for removing particles using the apparatus also is described.