Most frequent causes are deposits from not fully water-soluble inks or writing with too much pressure, which can shift the nib tines. Once the ink is dried up, simply topping up with new ink does not help; saturation rises and the feed clogs. Recommended are exclusively royal-blue, water-soluble Montblanc ink, regular and thorough cleaning as well as light writing pressure. With repeated nib problems, a workshop repair by Montblanc is justified; an annual repair necessity, however, is not the rule.