If you're going to scour those dishes, you'll need a sponge and some strong soap. To scour also means to examine something very, very closely. Looking for a job? Scour those classified ads!
When you scour something with your eyes, you examine or search it very closely. If you can't find the math homework you finished on Saturday, you'll have to spend some time on Sunday scouring your room until you find it. When you scour something with your hands, you scrub it very hard — often with a brush or pad — until the surface is spotless. For example, to remove the graffiti from the wall outside the restaurant, you'll have to scour it by hand, probably for hours.