All utensils have an exterior and an interior, and they have a tzeviah place. R’ Tarfon says: [It was said with regard] to a large wooden trough. R’ Akiva says: [It was said with regard] to cups. R’ Meir says: [It was said with regard] to tamei hands and tahor hands. R’ Yose said: [The Sages] stated this ruling only [with regard] to tahor hands.