The built-in music player is elementary OS works in a weird manner. I copied few albums in the default folder, Music but since then I can not get rid of any. There is no delete option in Noise and if I just remove it from the folder it still appears in Noise. How can I delete not wanted contents anyway?
There is a bug that could be related to this issue... If you are stuck though do this:
As an instant fix, close the app, then you can delete the entire database in ~/.local/share/noise/
Then relaunch and it should re-scan