Starting problems can have several causes: viscous or thick inks like some Montblanc inks cause skipping on certain nibs; Waterman inks often flow better. Dried ink residues clog the feed and can be removed by repeated flushing with cold water or soaking, possibly also in an ultrasonic bath, but not on wood or celluloid pens. With new pens with converter, the high adhesion of plastic can slow ink flow. A nib unsuitable for the writing position is also a frequent cause, especially with oblique nibs and signatures with a flying start. Paper also influences starting behaviour considerably; testing in specialist trade should be done with one's own everyday paper. With nib tipping grind, the nib's set angle decides whether ink flow starts reliably.