I recently had to deal with a stained white laminate counter top, due to a tea spill that wasn't cleaned up right away. I tried everything to clean it: thick bleach, baking soda (left on for two 24 hour periods), dish soap, all-purpose cleaners, and Vim powder; nothing worked! In fact, bleach seemed to darken the stain, and I suspect this is due to the hard water in our location.
What did work was a melamine "magic eraser", such as the Mr. Clean brand, but any type of melamine foam pad will work. Scrubbing really hard on the stain with the eraser did what no other cleaner could. Now the countertop looks just like normal, after a few sessions with the eraser. Save yourself a lot of trouble and just go with the melamine foam.
Link: http://ask.metafilter.com/18615/Getting-stains-out-of-a-white-formica-kitchen-counter
ThriftyFun is one of the longest running frugal living communities on the Internet. These are archives of older discussions.
How do I remove a hair dye stain and a rust ring from a shaving cream can off an old formica bathroom countertop?
How can I clean my formica countertop which is badly stained with all kinds of dirty marks? railroader