I attempted to suggest a better method to separate a refractory cast in order to solve the problems caused by bonding between refractory casts and ceramics in the firing-processing of all ceramic crowns as a part of dental prosthodontics. I emphasize the advantages and effectiveness of easy separation after firing by using the separating materials about the refractory cast dies. 1. We must not usse HF(55%) that is used as the chemical separating methods. 2. We decrease such methods as grinding, blasting, bur, and point 3. We can save time, costs and manual labors by using this methods. 4. This method regulates the expansion and constriction of heat because of the chemical reaction of the separating materials. 5. This method contribute to the breaking down without modification by minimizing the chemical and mechanical damages of the marginal and interior parts.