Related על גיטין 122:6

One who [brings his grain to be] milled at the place (i.e., the mill) of an am ha'aretz or the place of a Samaritan, he need not be concerned about impurity (cf. Dem. 3:4). One who [brings his grain to be] milled at the place of a Gentile, behold, he needs to be concerned about impurity.

They [may] store Terumah (i.e., the portion set aside for a Kohen, which must remain pure), at the place (i.e., a grain silo) of an Israelite (non-Kohen) am ha'aretz, but they [may] not store Terumah at the place of a Kohen am ha'aretz, since he has no shame in front of it.