This SAE Recommended Practice applies to determining worst- case fuel, conditioning test specimens in worst-case fuel(s) prior to testing, individual tests for properties of polymers exposed to methanol-gasoline fuel mixtures. The determination of equilibrium, as well as typical calculations are also covered. Polymers are used in applications which require exposure to a variety of fluid environments. Tests to determine the effects of such exposure on material properties are well established. However, the determination of the effects on polymers exposed to fuels of variable alcohol and ether content poses new problems. This document seeks to address those concerns by detailing changes to standard tests that make them suitable for that purpose.