Frequent causes are paper fluff between the nib tines, ink residues inside the cap or unsuitable paper; often a thorough cleaning of the cap with water and cloth helps. If the problem persists, a hairline crack comes into question, which requires a repair. The writing instrument should be sent in as an insured parcel, since registered mail in Germany is only insured up to 25 euros. Alternatively, sending in can take place via a Montblanc dealer or a boutique, which can also be found abroad via the dealer search on montblanc.com. Before a repair, the expected costs should be compared to the market price of a used 146; hairline cracks can also be glued by specialised repair workshops if appropriate.