משנה אויף עזרא 4:2

Even though they said, “they don’t exact pledges from women, slaves or minors, [yet] if they paid the shekel it is accepted from them. If a non-Jew or a Samaritan paid the shekel they do not accept it from them. And they do not accept from them the bird-offerings of zavin or bird-offerings of zavot or bird-offerings of women after childbirth, Or sin-offerings or guilt-offerings. But vow-offerings and freewill-offerings they do accept from them. This is the general rule: all offerings which can be made as a vow-offering or a freewill-offering they do accept from them, but offerings which cannot be made as a vow-offering or a freewill-offering they do not accept from them. And thus it is explicitly stated by Ezra, as it is said: “You have nothing to do with us to build a house unto our God” (Ezra 4:3).