Again a flush outlet is opened, but in this case the structure of the filter is designed so that the flush flow rushes over the face of the screen sweeping the debris along with it. Somewhat like hosing off a sidewalk with a strong stream of water. This is the most common method found in inexpensive filters. The most effective method of flushing is the backwash method, but these filters are typically more expensive. In this method the flush water is forced backwards through the screen for a very effective cleaning.
Most cartridges contain a paper filter which works just like a screen filter.
Most also remove organics well because the paper texture is rough enough to snag the organic matter. While some cartridges can be washed, most of them you simply replace when dirty. In most cases the media material is uniform sized, crushed sand. The water passes through the small spaces between the media grains and the debris is stopped when it can't fit through these spaces. Media filters are best for removing organic material from the water.