Dr. Fred Hueston of Stone Forensics has invented a new product: the Stain Sponge. “He has combined the necessary stone-safe surfactants and diatomaceous earths with the ease of a bag similar to those used in teabags, and invented the first easy-to-use poultice stain remover for stone products. By utilizing the stain process reversal technique, the patented Stain Sponge draws the stain from inside the stone,” the company says.