When in Rome do like the Romans.......When in Japan, at McDonalds, do like the Japanese do. This extra part of the trash can is for you to dump your remaining drink and ice, and then recycle your cup. I am not sure why they do the cups, but the extra drink and ice makes sense. Nothing worse than leaky garbage bags. The cups are made of paper so I wouldn't see a problem with them being in the trash, but hey that's just me.