When a watch arrives from the factory, I clean it by going into the bathroom, running the tap, and soaping the watch up as if I was washing my hands. Then I apply sewing machine oil to the bracelet, flex the links to really work the oil in, then it's back with more soap and under the tap. As for scratches, depends how severe they are... Nail polishing boards are good for getting a good shine, but the watch will only get more scratches when it's worn, so a bit of a waste of time, really. If you can't completely de-case the movement in the event of the case flooding, you may want to ignore the soap and water approach