Magento Persistent购物车不工作，不清除购物车项目？

Magento version: 1.9.0.1

Issue: Persistent Shopping Cart is Enable Persistence Yes and Persistence Lifetime (seconds) is 60 second. , but cart is not clearing even i wait more than 30 mins.

I see this question asked by someone 2 years ago in magento 1.7 but no answer. stack overflow question click here

I have followed this link instruction but not working Magento Persistent Shopping Cart settings

FYI: I feel it may affect from extension, So tested with fresh installation of magento 1.9 version. but facing same issue.

Anyone please help me.

In Magento is important to run a root/cron.php script each 5 minutes. It is activating time dependent actions.

http://www.magentocommerce.com/wiki/1_-_installation_and_configuration/how_to_setup_a_cron_job