Harsco CGFINE-50 50 lb Black Beauty 30/70 Fine Recycled Glass Blasting Media are high quality, chemically inert and contain less than 1% free silica produced from 100% recycled glass. Our crushed glass abrasive is utilized in a wide range of applications. This includes removal of surface coatings such as rust, paint and scale from a variety of substrates, especially stainless steel, aluminum, concrete, brick and wood.