A microwave heating package, and a method of microwave heating. Both the package and the method employ a lossy chemical susceptor which upon continued exposure to microwave radiation becomes substantially microwave transparent, thus building into the system a unique maximum temperature shut off at the point at which the chemical susceptor becomes microwave transparent. The chemical susceptor is comprised of a combination of a solute, such as inorganic salts of Group IA and IIA, and a polar solvent for the solute, such as water. The chemical susceptor may be composed of a hydrated form of the inorganic salts. The package, method and chemical susceptor may be used for microwave heating of many products, including among others, food products.