This article provides instructions on how to delete contents in a Google My Drive. 

folders and their contents have no individual “ownership”. The roles (Viewer, Commentor, Contributor, Content Manager, or Manager) define who and what you can do with a file or folder. Your role can be different for each file and folder within the My Drive. For example, you can only have View permission on a folder but actually be a Manager for a file within the folder. As a result, it is conceivable that there are files/folders within your My Drive that you do not have edit access to. Without this, you cannot delete them.

Because of this, it is not possible to delete non-empty folders within your My Drive. Instead, you must:

1. Be assigned to the Manager role for the files, folders to be deleted. 
2. Navigate to your My Drive.
3. Delete all files within each folder.
4. Delete all empty folders.
5. Wait. If you have a large number of files and folders to be deleted, it can actually take time for them to be deleted on Google's servers. So, if you have an empty folder, but still can't delete it (see next step), come back later and try again.