A general poultice with baby or baking soda and water is the best remedy. First, moisten the surface of the granite with the same liquid that made the paste. Then apply the poultice paste to the granite surface about ½” thick. Tape plastic sheeting over the poultice area, and allow it to sit for 48 hours. Remove the poultice with a spatula, rinse the cleansed area with clean water, wipe off excess water, and allow the surface to dry.Granite tends to attract soap scum. Rinse with hot clean water on a regular basis and use a paper towel to dry. Another way to remove lime build up , soap scum, stains or dried spills, is to use a straight razor blade in a gentle scraping motion. Do not use lime removal products or cleaning products that contain ammonia, as this will affect the seal on the stone.
For stubborn stains you can also use dry steel wool grade 00, or a no-scratch Scotch Brite pad to try to remove them.