Ordinary household cleaners remove the stone's protective sealer and damages the stone's surface. To test the seal on your natural stone countertops, perform this simple test: place a small amount of water on your natural stone countertop and allow to sit for 20-30 minutes, then wipe away. If the water leaves a darkened spot on the stone, you need to use Granite Gold Sealer to reseal your natural stone countertop. Granite Gold Sealer should be used once or twice a year, depending on what type of stone. For example, lighter-colored granites should be sealed twice a year compared to once a year for darker-colored granites, which are less porous.