Remove attribute from entity

Question

I added attributes in this way without problems:

$this->startSetup();
$installer = new Mage_Sales_Model_Resource_Setup('core_setup');
$entities = array(
    'quote_item',
);
$options = array(
    'type'     => Varien_Db_Ddl_Table::TYPE_DECIMAL,
    'visible'  => true,
    'required' => false
);
foreach ($entities as $entity) {
    $installer->addAttribute($entity, 'packing', $options);
}
$installer->endSetup();
$this->endSetup();

But when I try to remove the attributes it gives me error: WRONG Entity ID:

$this->startSetup();
$installer = new Mage_Sales_Model_Resource_Setup('core_setup');
$entities = array(
    'quote_item',
);
foreach ($entities as $entity) {
    $installer->removeAttribute($entity, 'packing');
}
$installer->endSetup();
$this->endSetup();

Answer 1

$setup = new Mage_Eav_Model_Entity_Setup('core_setup');
$attribute = 'packing'; 
$setup->removeAttribute('quote_item', $attribute);
$setup->endSetup();