A method of filtering contaminants from a fluid is disclosed. A feedstream of fluid containing contaminants is directed into a filter chamber containing a filter element. Part of the feedstream fluid flows in one of: a forward flow direction where it passes in a first direction through a wall of the filter element; and a reverse flow direction where it passes in a second, opposite direction through the wall. The filtrate is directed into a flowline for collection. The feedstream fluid is then arranged to flow through the filter element in the other direction, to remove contaminant material from a surface of the element wall. Following removal of contaminant material, the feedstream fluid is continued to be directed through the wall of the filter element in said other direction, to filter out contaminants from the fluid during flow in said other direction.