Method for removing a fluid from a a vessel comprising a penetrable cap

perforable cap (30A-E), comprising: a closed side wall (35) having an inner surface (40), an outer surface, a top surface (48) and a lower surface (37); means (36) for fixing the cap (30A-E) to a container open end (20) in sealing engagement; a flange (39) extending radially inwardly from the inner surface (40) of the side wall (35) of the cap (30A-E) and having an upper surface (43), a bottom surface (42) and an end surface (62) defining the end surface (62) of the flange (39) having an opening sized to receive a device (90) fluid transfer so that the inner surface (40) of the sidewall (35) of the cap (30A-E) and and the top surface (43) of the rim (39) define a first bore (44); a first frangible seal (32) to prevent fluid passage (100) from an interior space of the container (20) defined by the side wall (22) and a bottom wall (26) of the container (20) into the first hole (44), the first seal (32) to the top or bottom surface (43) or (42) of the flange (39) being fixed; filter means (33) to hinder or prevent the release of an aerosol or bubbles from the interior of the container space (20) into the atmosphere, the filtering means (33) being disposed substantially within the first bore (44); and retaining means (34A-D) for containing the filter (33) within the first bore (44).