Narrated by:Ibn 'Abbas that
It was narrated from Ibn 'Abbas that:The Prophet said: 'Rinse your mouths after drinking milk for there is some greasiness in it."
حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ إِبْرَاهِيمَ الدِّمَشْقِيُّ، حَدَّثَنَا الْوَلِيدُ بْنُ مُسْلِمٍ، حَدَّثَنَا الأَوْزَاعِيُّ، عَنِ الزُّهْرِيِّ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ بْنِ عُتْبَةَ، عَنِ ابْنِ عَبَّاسٍ، أَنَّ النَّبِيَّ ـ صلى الله عليه وسلم ـ قَالَ " مَضْمِضُوا مِنَ اللَّبَنِ فَإِنَّ لَهُ دَسَمًا " .
IbnMaja
The Book of Purification and its Sunnah • Hadith 498