Flush with water! General water washed stone, pebble, after oxalic acid or low concentration of hydrochloric acid immersion, the dirt of the skin and impurities included in the cracks in the holes can be quickly removed, off, and then washed with water after residual acid, stone skin will appear very clean, smooth, such pickling is only to remove dirt and dirt, but also the essence of the stone with hydrochloric acid can be.