An oil-collecting can (500) for a filter cartridge (300) comprises a plurality of capillary ribs (530) that are sized and shaped to contact filter media in the outlet chamber. The oil-collecting can (500) can be used in conjunction with a filter cartridge (300), which is installed in a filter assembly to encourage the downward flow of oil droplets. Such a filter assembly could be used, for example, in a crankcase ventilation system, to remove particulates and other contaminants from piston-bypass fumes.