Plastic, drinking cartons and metals are collected in the same container. These three are separated using magnets[1] and infrared scanners. The plastics are melted down to little pellets that can be used to create new products. A common example are shampoo bottles. This video is in Dutch, but it has some overview of these sorting machines: https://www.youtube.com/watch?v=Gf--8o3yD6g
Based on this video about plastic recycling in Germany, I think the situation is very similar there: https://www.youtube.com/watch?v=I_fUpP-hq3A The video is in English. The plastics that are recycled there seem to be PET, PP and HDPE.
I'm absolutely in love with all the neat little tricks these machines use to sort the stuff. From simple ones like sieves and centrifuges, to fans and advanced imaging stuff. It's beautiful.
[1] Even aluminium can be sorted with magnets by doing some magic.
For example, I'm reading this article from 2011 that mentions that 77% of Japan's plastic is recycled: https://www.theguardian.com/environment/2011/dec/29/japan-le...
Is that complete bullshit too, or is something possible to actually achieve, just not in the US?