Here are instructions for Parker Vacumatic Filling fountain pens, including Parker Vacumatic and 51s: Unscrew the barrel end blind cap. Place entire nib and half the section into the ink. Press the button 7-10 times pausing a second between strokes. Screw blind cap in place. Remove from the ink and wipe nib after filling. Always place cap onto the pen with the nib pointing up, do not put the pen into the cap with the nib pointing down - this will prevent ink from getting into the cap.