In order to delete a project:
The project must have no resources in it. To empty out the resources in a project, you can either destroy them or move them into a new project.
The project must not be the default project. You can set a different project as the default on the Settings tab of that project.
To delete a project after you have removed all of its resources:
Visit the project’s Settings tab.
Click Delete Project. You will only be able to select the Delete Project button for empty, non-default projects.
When prompted, press Confirm Delete.