When you are done with a campaign, you may want to delete the layout associated with that campaign. This can help to avoid confusion in future campaigns.
From the Dashboard, click on CRM and select Lead Layouts & Fields from the drop down.
In the Manage Layout Section, click on the ACTIVE button to turn off the layout. The layout must be Off before you can delete it. Click on the Action gearwheel then select Delete from the drop down.
Click on Delete button.