ASTM D6185:
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1.1 This practice covers a protocol for evaluating the compatibility of one or three binary mixtures of lubricating greases by comparing their properties or performance relative to those of the neat greases comprising the mixture.
1.2 Three properties are evaluated in a primary testing protocol using standard test methods: (1) dropping point by Test Method D 566 (or Test Method D 2265); (2) shear stability by Test Methods D 217, 100 000-stroke worked penetration; and (3) storage stability at elevated-temperature by change in 60-stroke penetration (Test Method D 217). For compatible mixtures (those passing all primary testing), a secondary (nonmandatory) testing scheme is suggested when circumstances indicate the need for additional testing.
1.3 Sequential or concurrent testing is continued until the first failure. If any mixture fails any of the primary tests, the greases are incompatible. If all mixtures pass the three primary tests, the greases are considered compatible."