You can use P4Web to delete label specs, branch specs, and job specs.
NOTE: Deleting a spec is permanent.
 To delete any spec:
- From the Labels, Branchs, or Jobs tabs, click on the name of the spec that you want to delete.
  
 - Select Delete spec from the Action menu, where spec 
    is the type of spec that you are deleting: label, branch, or job. 
    
 - A confirmation page is displayed.
      - To delete the spec, click Yes. 
      
 - To return to the spec without deleting it, click No.