Agra Grit Walnut Shell Media 18-40 Grit is available in a pack of 25lbs. Agra Grit Walnut Shell Blasting Grit is safe for you and the environment. Silica free material reduces your risk of Silicosis. Walnut Grit is softer than sand, and when used properly maintains the integrity of underlying structure. Great for removing graffiti, cleaning engines and transmissions, soft metals, preparing metal for paint, and restoring historical items. The uses are endless! Less damage to the substrate means the job gets completed faster. A great non-toxic solution for your blasting needs. These crushed walnut shells for blasting, polishing, and other applications are sustainable, biodegradable, GMO-free, Asbestos-free, have no heavy metals, and are not chemically processed. About the Brand. Eco-Shell was founded in 1995 to provide biodegradable, non-toxic, environmentally safe, and cost-effective walnut shell products to an array of industries. Eco-Shell is one of the premier suppliers of walnut shell media to industrial markets around the world. As a result of having a substantial in-house raw material supply partner, Eco-Shell is capable of entering long-term contracts and can guarantee a consistent supply without interruption.