Muwatta Malik:Zakat:Hadith 648
حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَبْعَثُ بِزَكَاةِ الْفِطْرِ إِلَى الَّذِي تُجْمَعُ عِنْدَهُ قَبْلَ الْفِطْرِ بِيَوْمَيْنِ أَوْ ثَلاَثَةٍ ‏.‏

Yahya related to me from Malik from Nafi that Abdullah ibn Umar used to send the zakat al-fitr to the one with whom it was collected together two or three days before the day of breaking the fast.