The problem is a classic ventilation and adhesion issue: in the converter an air cushion must always remain between piston and ink, otherwise the pressure ratios change while writing and the ink flow breaks off. Even with sufficient air space, ink can adhere to the plastic walls because different converter plastics have differently strong adhesion forces; this was particularly pronounced on some Graf von Faber-Castell converters, less strong on Montblanc. Montblanc places a loose metal spiral in newer converters that keeps the ink moving and largely eliminates the problem; the current Parker piston converter also uses a spiral. A practical remedy is cleaning with diluted soap solution to reduce adhesion, or switching to cartridge or piston pens, on which the problem does not occur or only in a strongly mitigated form by design.