When you have a lead you may have created to test out the system, or a duplicate was created, you will want to delete it from your account so it doesn't affect your business data and reporting.
To completely delete a lead or job from your account, you'll want to first choose the Close option in the right column when viewing the lead/job's Overview screen.
After choosing a close reason (here you can choose anything since you'll be deleting it), you'll then see the option to Purge it on the next screen. This will permanently delete it from the database as if it never existed.
Any contracts, questionnaires, quotes, orders, notes, and tasks associated with the lead or job will be purged with it. However, the contacts on the job worksheet will not be purged. You can purge them from the Address Book itself.
Important Note: Be sure that you really want to delete it, as it cannot be undone.