A dirt separator for a vacuum cleaner including a chamber having an inlet through which dirt-laden fluid enters the chamber and an outlet through which cleansed fluid exits the chamber; and a disc located at the outlet, the disc being arranged to rotate about a rotational axis and including holes through which the cleansed fluid passes. When viewed normal to the disc, each hole is elongate and defines a longitudinal axis which runs within the plane of the disc. The longitudinal axis of each hole is inclined relative to the radial direction of the disc.