A rather dainty name for a messy business, Darling Ingredients is the largest publicly traded rendering operation in the US; it collects and recycles animal by-products, used cooking grease, and bakery waste, and offers grease-trap cleaning services. It counts restaurants, butcher shops, grocery stores, and independent meat and poultry processors among its customers. Darling also produces yellow grease, tallow, and meat, bone, and blood meal. The company sells its products nationwide and overseas to makers of soap, rubber, oils, pet and livestock feed, and chemicals.