How do you delete a Channel?
No. You can not delete a channel once it has been created. You can deactivate a channel by hiding it.
Hiding a Channel
To hide a channel, deselect the Enabled check box within View Channels and press Submit. Hiding a channel will hide all its child channels as well.
Note: All creative targeted to the hidden channel and its children will immediately stop serving. Do this only if you are certain that hiding the channel will not impact your ad serving.