Refer to a thread I've posted:
http://www.askmehelpdesk.com/skin-li...ic-202357.html
You can combine natural products like lemon juice, green tea, mulberry extract, distilled water, and licorice extract.
Trust me, I've just applied pure licorice extact to an undisclosed area in my leg and it's whitened quite a bit so be careful and make sure to dilute extracts with water to decrease potency.