1 Auxiliary Agents for Metal Casting Work to Protect the Sand Molds and Cores and to Produce Smooth, Clean Surfaces on the Cast Objects-Namely, Chemical Heat and Fire Resistant Insulating and Separating Agents, Smoothing Agents, Blackening Agents, Surface Hardening Agents for Molds and Cores (Except Spreading Agents in the Form of Lacquers and Paints)