cck delta values: delta with leading space = "historical change," no leading space = "multiple selection?"
Use a custom module and unset the field items using hook_form_alter(), or do it in your themes template.php.

/**
* Implements hook_form_alter().
*/
function YOUR_THEME_form_alter(&amp;$form, &amp;$form_state) {
  if ( $form_id= 'YOUR_FORM_ID' ) {
    unset($form['YOUR_FORM_FIELD']);
    // ... ADD MORE
  }
}