Remove menu item from display
If I understand well your question, you can use theme_menu_item_link() function to your template.php of your theme.

This is an example that I have tested (in this example Garland is the theme used, so you must replace the name of the function with the respective name):

Here is the example menu:



This is the function to remove the items:

function garland_menu_item_link($link) {
  if (empty($link['localized_options'])) {
    $link['localized_options'] = array();
  }
  if ($link['title'] != 'item 1') {
    $link['localized_options'] += array('html' =&gt; TRUE);
    return l('&lt;span&gt;' . $link['title'] . '&lt;/span&gt;', $link['href'], $link['localized_options']);
  }
  else {
    unset($link);
  }
}




Please note that I have added if($link['title'] != 'item 1'){.. to detect the menu item, and remove it (with unset($link)). 

This is the code for changing the text:

function garland_menu_item_link($link) {
  if (empty($link['localized_options'])) {
    $link['localized_options'] = array();
  }
  if ($link['title'] == 'item 1') {
    $link['title'] = 'new text';
  }

  $link['localized_options'] += array('html' =&gt; TRUE);
  return l('&lt;span&gt;' . $link['title'] . '&lt;/span&gt;', $link['href'], $link['localized_options']);
}




Remember to clear the cache to see the changes.

I found these other resources related with theme_menu_item_link(): http://drupal.org/node/245156, http://drupal.org/node/249864, http://drupal.org/node/417482.