The surface you refer to is called plastic laminate or, more commonly, Formica (Formica is a registered trademark). There are two different finishes on plastic laminate counters: slick plastic laminate (which is shiny or glossy) and dull plastic laminate (such as butcher-block or leather-grain look). In either case they can be washed with a damp rag and wiped dry. Never use abrasive cleansers on plastic laminate because it will scratch the surface and eventually remove the finish. Most stains can be removed by squeezing a fresh lemon over the ugly area. Let is soak for about 1/2 hour, then sprinkle some baking soda over the lemon juice. Scrub it with a terry cloth rag, rinse and wipe dry.