Follow instructions below to delete your own user-defined columns to the campaign dashboard. 

How to Delete a User-Defined Column

1. Hover over  and select  to start.  
2. On the Campaign Dashboard page, click on the  icon. 
   
   
   
   
3. Click the  icon next to the user-defined column that you want to remove.
4. Confirm that you want to delete the column in the popup 
   
   
   
   
5. Click the  button
6. Your user-defined column and all the values that were previously stored in it have been removed.