Rashi on Leviticus 6:21/רש"י על ויקרא ו׳:כ״א

1ישבר [BUT AN EARTHEN VESSEL WHEREIN IT IS SODDEN] SHALL BE BROKEN — because the substance absorbed in it becomes what is known as נותר (the technical term for any portion of a sacrifice not eaten by the time prescribed for this) (cf. Avodah Zarah 76a). That, too, is the regulation applicable to all sacrifices (i. e. that an earthen vessel wherein they have been cooked must be broken).

2ומרק — of the same root and meaning as the noun in (Esther 2:12) “the things for purifying (תמרוקי) women”; escourement in old French; English, scouring.

3ומרק ושטף [AND IF IT BE SODDEN IN A COPPER POT] IT SHALL BE BOTH SCOURED AND RINSED [IN WATER] — in order that it should give out what it has absorbed: but as far as an earthen vessel is concerned Scripture teaches you that it can never get rid of its taint (lit., can never leave the grasp which its taint has on it) (Avodah Zarah 34a; Pesachim 30b).