ring not shown cap 1 exhibits a passageway 7 for receiving a displacement pin not shown from the receptacle not shown the passageway 7 is sealed by a rubber grommet head 9 of the plunger 11 plunger guides 13 and 14 and o ring 16 stabilize the rubber grommet head 9 and effect sealing when the rubber grommet head 9 is in the sealed position illustrated in fig6 and 7 the plunger 11 is further stabilized by a plunger sleeve 15 the plunger 11 is fixed to a first magnetic plate 17 in the sealed position illustrated in fig6 and 7 the magnetic attraction between the first magnetic plate 17 and a second magnet plate 19 fixed to plunger guide 13 biases the grommet head 9 of plunger 11 against the interior surface of the passageway 7 sealing the cap 1 in the unsealed position illustrated in fig5 and 8 a displacement pin not shown from a receptacle presses the rubber grommet head 9 of the plunger 1 away from the interior surface of the passageway 7 causing the plates 17 and 19 to separate and opening the cap 1 to allow ink to flow through the passageway 7 upon removal of cap 1 from the receptacle and hence removal of the pin not shown from the passageway 7 the magnetic attraction between plates 17 and 19 causes the plates to be drawn together as shown in fig6 and 7 resealing the passageway 7 an alternative embodiment of the present invention is illustrated in fig1 14 cap 21 illustrated attached to bottle 23 exhibits exterior threads 25 for inserting the cap 21 and bottle 23 into a receptacle not shown by.