Possible meanings are 1) "separates himself from dishonorable people" or 2) "makes himself pure." In any case, Paul speaks of this process as if it were a person washing himself. (See: [[rc://en/ta/man/translate/figs-metaphor]])
Paul speaks about this person as if he were an honorable container. Alternate translation: "he is like the container that is useful for special occasions" or "he is like the container that is useful for activities good people do in public" (See: [[rc://en/ta/man/translate/figs-metaphor]])
This can be stated in active form. Alternate translation: "The Master sets him apart, and he is ready for the Master to use him for every good work" (See: [[rc://en/ta/man/translate/figs-activepassive]])
He is not set apart physically or in the sense of location, but instead to fulfill a purpose. Some versions translate this "sanctified," but the text signals the essential idea of being set apart. (See: [[rc://en/ta/man/translate/figs-metaphor]])