You can delete a Label that you do not want anymore

Steps

1. Click on the Cog Icon of a story.
   
   

   Open

   

2. Select Label option
   
   

   Open

   

3. Search the label you want to delete and find it

4. Click on the Edit option of the label which is present below the name of the label.
   
   

5. The Edit label box appears.

6. You can see the Delete option at the bottom.
   
   

7. Click Delete.

This will delete the label and remove it from all the stories it is attached to.