The most common cause of intermittent ink flow is dried ink in the feed, especially when the pen has not been used or only sporadically over longer periods and was not flushed before being put away. Recommended is multi-day flushing with clear water; with strongly resinified residues, soaking the front section in water or an ultrasonic bath helps. Breaking in a new nib is a long process, since the iridium grain at the tip is only polished by use over long periods; a hasty nib swap is not the way. If the ink flow cannot be stabilised by cleaning, the writing instrument should be presented with a writing sample to a specialist shop so that nib geometry, hand position and writing angle can be assessed in interaction.