Pumice stones are often used to clean the grout around shower tiles because of their abrasive nature. The pumice will eliminate the white film that can develop on these surfaces over time. Then again, it is essential to use caution when using a pumice stone. The abrasiveness can also damage the surface of the tile or grout if not used correctly. It is best to test the pumice stone on a small area first to ensure it will not damage the surfaces. Using the pumice stone, use gentle strokes and avoid scrubbing too hard. With proper care, a pumice stone can help to keep grout and tiles looking new.