Chat rooms cannot be deleted. If you have a chat room that is no longer in use, you can disable it. For details, see Disabling or Enabling a Chat Room.
If you also want to clear permanently deactivated channels out of your main category structure, you can create a new category whose sole purpose is to contain them.
Categories can be deleted, but only if they do not have any chat rooms or subcategories nested under them. Before you delete a category, you must move all nested chat rooms and subcategories to a new parent category. For details, see Moving a Chat Room or Category.
To delete an empty category
In the Chat Roomslist, right-click the category to delete, and then click Delete.