&gt; after period of conversion, which I believe has ended a long time ago in the original EUR-countries<p>That depends on the issuing country. I&#x27;d guess it&#x27;s related to whether they expired their banknotes before the Euro.<p>French and Dutch banknotes are now invalid, but German Deutschemarks are valid for exchange at any Bundesbank indefinitely. The same applies to Austrian and Estonian currency.<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Deutsche_Mark" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Deutsche_Mark</a><p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Austrian_schilling" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Austrian_schilling</a><p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Estonian_kroon" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Estonian_kroon</a>