Are Black Quartz Countertops Hard To Keep Clean . (perhaps it’s thanks to the simplicity and contrast and the plain old goodness of black and white). A modern, statement shade that will always look stunning. How to Clean Quartz Countertops Simple Green from simplegreen.com Wring out and rewet the cloth or sponge, then go back over the countertops one more time to clear away any last traces of soap. Using the right sealant can help you protect your quartz countertop from harsh stains and spills. Or ordinary dish washing detergent e.g.