Collectors report repeated problems with certain third-party inks, especially Private Reserve, which in small Montblanc models like the Mozart lead to heavy 'soup' where cap and grip section are full of ink after a short time; comparable effects also occurred with a Pelikan M200. Thorough flushing before changing does not reliably eliminate the problem, since the small pin that opens the cartridge seal, or other components, can be permanently impaired by aggressive inks; even after returning to the original Montblanc cartridge the soup often continues to appear. Other inks, e.g. black inks from older inkjet cartridges, run by contrast without problems in larger models such as the 146. Anyone using third-party inks in smaller Meisterstücks risks a repair, in which Montblanc typically renews the front section and feed and only retains the old nib; the maker's note to use only Montblanc ink therefore has practical justification.