Occasionally one of your Lightboxes will outlive its usefulness or start to get on your nerves. To get rid of it for good, follow these steps.
From Your Account
Hover over your name.
Click Lightboxes.
Locate the undesired lightbox.
Click the trash icon next to its name.
Confirm your choice.
While Browsing
Hover over the name of the lightbox.
Select Delete from the dropdown menu.
Confirm your choice.