During the German occupation of the Netherlands, all kinds of ways were devised to express resistance to the Germans and support for Queen Wilhelmina and the Dutch government in London.
Certainly at the beginning of the war, when there was still no question of organised resistance, this was often shown in a more or less playful way. These acts became known as "silent resistance." Often these forms of defiance were banned and forbidden by the occupying forces, after which something new was devised.
In 1941 the Germans seized all the silver and copper coins. This was on the one hand because the old coins bore the image of Queen Wilhelmina, on the other hand the metal was used for the German arms industry. The people had to hand in their old coins in exchange for new zinc coins or paper money. However, many Dutch people kept their old coins and turned them into jewellery, which was worn as a symbol of resistance and as a reminder of the royal family.
In 1941 the Dutch section of the BBC called for the V for Victory to be used, by making a V symbol with the fingers, or by wearing a pin with a V. A month later the National Socialists in the Netherlands hijacked the V, and posters appeared everywhere with the text: 'V = victory, because Germany wins for Europe on all fronts'. Since then, the V-sign was used by both sides.
The Dutch lion
The Dutch heraldic lion (a "climbing" rampant lion, holding a sword in one paw and arrows in the other) was also used by both sides: it could be found on resistance pins, but also on the uniform of the Weerbaarheids ('Defence') section of the National Socialists.
The Dutch flag
The Dutch flag was never officially banned during the occupation. It remained the national flag, but its use was strongly discouraged by the Germans. On royal birthdays, wearing red, white and blue clothes or hanging red, white and blue laundry was regarded as an act of defiance.
Another symbolic form of resistance was the carrying of a match in a buttonhole, with the (orange-yellow) head up, to which different meanings were given: "head up", "orange up", "burning with hatred".
For silver jewellery, see the TRC blog, 'Dutch jewellery with silver coins from the Second World War', by Gillian Vogelsang, 20 September 2020.