If you no longer want your guide to be public, you can change the status to "Disabled" and save it for later use. If you're sure that you won't need it again, you also have the option to delete it permanently.
Deleting a Guide
To delete a guide, first choose "Guides" from the left-hand navigation menu. You'll see a list of your guides and a column that shows the "Status" of each guide. Click the Status drop-down next to your guide and you'll see the "Delete" option at the bottom.