code: public function purgeSubscriptions()
  	{
  		$objRecipient = NewsletterRecipientsModel::findExpiredSubscriptions();
  
  		if ($objRecipient === null)
  		{
  			return;
  		}
  
  		foreach ($objRecipient as $objModel)
  		{
  			$objModel->delete();
  		}
  
  		// Add a log entry
  		$this->log('Purged the unactivated newsletter subscriptions', __METHOD__, TL_CRON);
  	}
docs: Purge subscriptions that have not been activated within 24 hours