If more than one portion is required to represent a lot or shipment of grease softer than 175 penetration (see Test Method D 217), prepare a composite sample by mixing equal portions thoroughly. Use a large spoon or spatula and a clean container. Avoid vigorous mixing or working of air into the grease. As grease samples become partially “worked” in being removed from containers, the procedure is not suitable for obtaining samples of greases softer than 175 penetration on which unworked penetration is to be determined. For greases having a penetration of less than 175, cut samples from each container with a knife in the form of blocks about 15 by 15 by
5 cm (6 by 6 by 2 in.). If required, make unworked penetration tests on blocks as procured and other inspection tests on grease cut from the blocks.