If you post an article to the wrong class board by accident or write a comment on a post but it didn't come out the way you wanted it to, don't worry! Deleting pins and comments is really straightforward.
Just go to the post you want to delete and select the X button on the upper right of the post. You can also edit the same post by pressing the pen symbol to the left of the X button.
Deleting/editing a comment works much the same way.