You can delete environments & projects through the devshop web UI.
Environments, by default, must be disabled before being deleted. This is to help prevent accidental destruction of your environment.
To disable your environment:
Find your environment in the web UI.
Click the Environment Settings icon on the environment box.
Click Disable at the bottom of the drop down.
On the confirmation page, click the Disable button.
The environment will then run it's Disable Task. Once complete, it will change appearance and have the word "Disabled" displayed in the UI.
At this point, you can either Enable the environment or Delete the environment through the Gear icon.
If you are sure you want to delete the environment:
Click the Environment Settings icon on your disabled environment.
On the confirmation page, click the Delete button. You will not be able to recover once you press this button.
Once the Delete Task runs, the environment will disappear from the Project Dashboard.
If, for some reason you want to be able to delete sites without having to disable them first, visit the Admin > Hosting > Settings page. Uncheck the box that says Require site to be disabled before deletion.
This is not recommended. Please use caution when using this setting.
To delete a project and all of it's environments:
Visit the Project Dashboard for the project you wish to delete.
Click Settings, then Project Settings.
Scroll down to the bottom of the settings page and click the Delete this project link.
On the confirmation page, click the Delete Project button. This cannot be undone!
Your project, and all of it's environments will be scheduled for deletion once you hit this button. It will take a few seconds for each environment to be deleted, so please be patient.