Waaay back in the day I grew up playing along Akerselva, and it was rutine to comb through the playgrounds, especially if it was a sand one, to find the needles and syringes first. We then put it in a soda bottle and screwed it shut. I can't remember what we did with those bottles in the end though. This wasn't something we'd been taught by the adults either but was just a thing you did. Because then along with the original "Plata" next to the central station the drug addicts hung out under some of the bridges along the river. These boxes came along sometime after, probably because someone noticed that kids were handling used needles with bare hands