Unable to delete feature content type after uninstalling feature
Solution

Using a hook_uninstall() in FEATURE_NAME.install file and changing the status of the content type, so the system thinks it is an unlocked, custom content type.

I posted this also on d.org.

&lt;?php
/**
 * Implements hook_uninstall().
 */
function FEATURE_NAME_uninstall() {

  // List custom content types added by this feature
  $custom_ctypes = array(
    'blog',
  );

  // Go through each and unlock the content type
  foreach ($custom_ctypes as $ctype) {
    db_query("UPDATE {node_type} SET `custom` = 1, locked = 0 WHERE type = :ctype", array(':ctype' =&gt; $ctype));
  }

  // Clean Drupal cache; this is necessary for the "Delete" link to appear
  // next to the content type created by the feature.
  drupal_flush_all_caches();

}


This will make the "Delete" button appear for that content type, so you can delete it from the admin.

Hope this helps someone!