The Rules of the Yardsale are included in the general rules, which you agreed to when joining the forum:
Editing is not available in the Yard sale, this stops any misunderstandings that may arise or possible dodgy procedures: e.g. if a description was changed after a sale took place.
To update anything you can make another post (as long as it's not purely to bump the thread), or contact admin to edit any mistakes in existing posts.
When an item is sold, we do not remove posts, however you can contact admin to edit the prefix to show the item as SOLD.