On the Montblanc 31, by factory design, the front section and barrel are screwed, not glued; sealing is provided by a sealing ring that is set firm by the thread. If the front section can be pulled off without a thread, this regularly indicates a clean break or an earlier improper repair attempt in which the original thread was lost and the parts were then glued. Adhesive residues inside the front section as well as the absence of a recognisable thread starting point typically confirm this finding. In this case the pen is usually only fit as a parts donor; attempts to glue the connection again rarely lead to lasting results because of the ink-tightness required. Models from the 1950s can otherwise be unscrewed without problems for cleaning, with the rings not being mixed up.