A filter assembly for a removable dirt separation system is disclosed. The filter assembly includes a wall support attached to a wall of the dirt separation system and a screen panel having a number of screen elements. The filter assembly further includes a filter element which is selectively releasable from the screen panel. The screen panel and filter element can be selectively secured to the wall support. A fine particle separation chamber is at least partially defined by the screen elements and the filter element. A portion of the walls of a dirt cup within the dirt separation system is formed by the filter assembly. A method of operating a filter assembly for a removable dirt separation system is also disclosed.