There is a work around that works for my Android cellphone. I'm not sure it will work for all devices but its worth trying.
1. Turn off the Autoplay option in settings (you don't want the app adding more "similar" music to the queue).
2. Create a brand new Playlist and name it "Clear Queue" (or whatever will help you remember that the playlist's purpose in life is simply to get rid of your queued music).
3. Add a short song to the newly created playlist. (I use "Taps" because its only 54 secs long and represents the death of my queued music).
4. Choose to play that playlist. (What should happen and what does happen on my phone, is that the currently queued songs are immediately replaced by the new playlist's songs ... of which there is only the one song. So now the queue contains only the one song instead of the hundreds it used to have).