Widget cleanup — Removing "Inactive sidebar (not used)"

In Widgets, I have about a half dozen “Inactive sidebar (not used)” that are NOT within the “Inactive widgets” area; and they are not within 'wp_inactive_widgets' either.

I have found several posts pertaining to cleaning “Inactive widgets”.

For example:

$widgets = get_option('sidebars_widgets');
$widgets['wp_inactive_widgets'] = array();
update_option('sidebars_widgets', $widgets);

However, $widgets['wp_inactive_widgets'] comes up empty.

Suggestions for were I can find these “Inactive sidebar(s)” so that I can leave Widgets clean?

They are not inhibiting; but to others editing on the site, it can be confusing.

Thanks

Jeff in Seattle