In order to archive an category, log into your account and navigate to Products > Settings> Categories.  The screen will contain two sections, one for active categories and one for archived categories. Find the category you wish to archive in the table and select Archive from the Actions menu.

Archiving a category prevents it from being selected as part of a product configuration. It is important to note that archived categories that are already attached to a product will continue to be seen by customers.

After you select Archive the category will be removed from the active section and placed within the archived section of the page.

If you need an archived category in the future you can easily reactivate it by finding the archived category in the archived section of the page and clicking Restore. The category will be added back into the active section and available for selection within product configuration.