Granite Countertop Staining

During construction, we were storing our Granite (http://tanbrown.org) Slabs (http://www.VerdeUbatuba.com) outside. Unfortunately, hickory nuts shells left by squirrels have left brownish stains, mostly on the bullnosed edges. What can we use to lighten or remove the stains?

We have heard many cleaning products normally thought of to remove stains are harmful to the polished surface. What about diluted bleach, Soft Scrub, baking soda paste??

Please help!