If I unsubscribe from the mailing list, I don't need the filter any more, and neither do I need the (now constantly empty) Yahoo! Mail folder I have created for the list. Time to delete it!
Delete a Folder in Yahoo! Mail
To remove a custom folder from Yahoo! Mail:
- Open the folder you want to delete.
- Move messages to other folders or delete them until the folder is empty.
- Click on the folder in the folder list with the right mouse button.
- Select Remove from the menu.
- Click OK.
Delete a Folder in Yahoo! Mail Classic
To delete a custom folder in Yahoo! Mail:
- Make sure the folder you want to delete does not contain any messages.
- Move or delete remaining emails.
- Follow the Edit link next to My Folders.
- Click Delete next to the folder you want to delete.
- The Inbox, Draft, Sent, Bulk and Trash folders cannot be deleted.
- Click OK.

