Can I delete a sandbox?

Yes. You can delete sandboxes. However, you can delete only those that aren't published.

Before you delete a sandbox, you must first confirm that the sandbox isn't active.

Caution: Deletion of partial content of a sandbox is risky. It's recommended that you don't use this option.

After you've tested your application changes, you must move those changes to the integration sandbox. Publish your integration sandbox and then delete all the test-only sandboxes. You can then create and work in new sandboxes, including a new integration sandbox.