The sample data is all located in a project. Delete the project and virtually everything will go (it might complain if you try to create a new project with the key of the sample project, but that's it)
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.