the spun composite fibers are drawn and subsequently extracted to porosify the sheath and to activate the sorptive property of the cores application_number US 15710280 A description the drawing schematically depicts in cross section a spinneret body 12 having an orifice 14 a fitting 16 is provided for connection to a polymer extruder a needle 18 having an open end 20 situated centrally of the orifice 14 is adapted for connection to a source of core slurry under suitable pressure in operation a blend 22 of polymer and pore forming material is extruded to form a sheath 24 having a lumen 26 and this lumen is simultaneously filled with a slurry 28 comprising particulate sorptive material in a liquid carrier in a preferred example the slurry is made by dispersing in a colloid mill active carbon particles pulverized to less than 325 mesh in triethylene glycol preferably the carbon is added progressively during the milling until it comprises approximately 25 percent by weight of the total slurry the slurry is then sieved with the aid of a brush through an 80 mesh screen in order to remove any large particles that might obstruct the flow of the slurry through the needle 18 the triethylene glycol is chosen as an extractable vehicle that will suitably carry the carbon particles and as a liquid having a sufficiently high boiling point to prevent flashing in the needle 18 that is vaporization in the presence of the heated polymer blend 22 it may also be preferred in some cases to heat the slurry to above the extrusion temperature of the blend for example with a polypropylene and wax blend the slurry.