The MIL-C-6529 specification establishes the requirements for mineral-base corrosion preventive compounds used to protect aircraft reciprocating and turbine engines During storage or shipment. This standard defines three specific categories based on their application: Type I is a concentrated additive designed to be mixed with operational mineral oils; Type II is a ready-mixed preservation oil specifically formulated for the higher viscosity requirements of reciprocating (piston) engines; and Type III is a ready-mixed compound intended for turbine engines that require low-viscosity mineral lubricants. These fluids are engineered to provide critical anti-corrosive protection while maintaining enough lubricating capability for limited engine operation during preservation procedures or short-term emergency use.