Abstract: Conservation of oily liquid sealant in coaxial odor trap cartridges for waterless urinals is accomplished in the present invention by the addition of a liquid-flow-diverting structure having at least one helical fin encircling the outer surface of the cylindrical partition that extends downwardly from the cartridge top cap. In a preferred embodiment two similar diametrically-opposed helical fins conserve sealant by modifying the otherwise vertical downward flow path to a downward incline that minimizes down-the-drain sealant loss by intensifying recovery of stray traces of sealant that become detached from the main layer of sealant and get swept along with the downward flow of wastewater in the outer chamber during a usage event. The sealant recovery action of the helical fins that takes place in the outer chamber is further enhanced by specially proportioning the cross-sectional flow area of the three chambers in the cartridge to maximize the cross-sectional flow area of the outer chamber.