Unload a scene that was generated at runtime

Unity Engine
1

I generate a new blank scene at runtime with:

SceneManager.CreateScene(“MyNewScene”);

Later I want to unload this scene and release it´s allocated memory, but because it´s not listed in BuildSettings I get an error: ArgumentException: Scene to unload is invalid.

How can I unload this scene and release its allocated memory?

2

Can you use a reference to that scene instead of the index or the name wehn unloadin?
public static AsyncOperation UnloadSceneAsync(SceneManagement.Scene scene);