You may wish to delete mock inspections, especially if you're still on your free trial. Save those free inspections for the real deal! Any inspection you haven't published can be deleted.
To find the inspection, navigate to the Schedule, or click your name > Inspections
Once you have located the inspection, click the More button in the top-right corner of Inspection Details
Then, select Delete
(Free Trial users, please note it sometimes takes a couple minutes for your "Used Inspections" count to go down.)