Hi Geert,
(Using English here because that's the forum's language.)
The Hohner Morino M series was built until around 1960 when Hohner stopped making the Morino and Excelsior took over, to make first the Morino N series and later he Morino S series. So your accordion is likely between 65 and 70 years old. If you were to look inside and know about accordions you could check whether it has Hohner Artiste reeds or Bugari tipo a mano reeds. The first are the older accordions, the ones with Bugari reeds are generally preferred and are younger. Both are pretty good, but when you go to sell the accordion it is rated higher when it has Bugari reeds than when it has Hohner reeds.
Such a Morino from the M series generally goes for somewhere around 2500 euro minus the cost to fix everything that's wrong with it (which is likely considerable unless the accordion was regularly maintained and tuned, something which is unlikely, especially in the Netherlands).
However improbably this may seem, a Hohner Morino IV M is easier to sell than a V M because it is more compact and lighter.
When you try to sell the Morino to an accordion dealer you won't get a lot for it. Better is to post it on "marktplaats.nl" and be patient for the right buyer to come along. With an accordion this old people will want to have a look inside, to check for instance whether the reeds are in good condition and not heavily rusted (which happens especially when the owner lives/lived near the coast). This accordion has no bellow pins, typically used to open it up. You need to unlock the bellows with the knob on the grille, then remove the grille, then turn the two levers in the front, and then the treble side kinda rotates off.
