The vast majority of homes have standard, very durable stainless steel sinks. There is a reason for this – they are inexpensive, stand up to years of use (and abuse), and can be cleaned up to look almost as good as new.
The most common staining with stainless steel sinks is the brown residue left when coffee is poured out, but not rinsed away. This discolouration can be a subtle yellow to a dark brown, especially if the sink is located at the office near the coffee station.
There are several solutions, the quickest is a cream cleanser and an SOS or abrasive scrubbing pad. If you don’t feel like scrubbing, a mild acid such as CLR will typically remove these and any hard water deposits. Just plug the sink and pour in at full concentration and leave overnight!
If the sink is very dull, or badly scratched you can polish it with fine steel wool, and metal polished typically found in the automotive isle for restoring the finish on aluminum wheels.
For acrylic, or solid surface materials check the underside of the sink for the manufacturers name and consult their web site for proper care instructions. Usually to remove minor staining an acrylic safe cleaner and/or melamine sponge (such as a Magic Eraser) will remove surface staining.
The best preventative cleaning is to rinse the sink after each use, especially after discarding coffee, tea, colas and tomato based foods.