Light rust will come out of formica by using a fresh cut lemon dipped in salt. Rub it in and rinse it off.
OR squeeze a fresh lemon over the stain. Let it sit for ½ hour, then sprinkle baking soda over juice and scrub with cloth, rinse, wipe dry.
OR clean dull formica use club soda, pour on club soda, wash, rinse with warm water, dry.
OR scrub in toothpaste and rinse.
Give the countertop a light coating of paste wax (like turtle wax) to bring up the shine.