It was narrated from Ibn Wa’lah that he asked Ibn ‘Abbas:
“We are attacking the Maghrib, and they are people who worship idols, and they have waterskins in which they keep milk and water.” Ibn ‘Abbás said: “Tanning is purification.” Ibn Wa’lah said: “Is this your own opinion, or something that you heard from the Messenger of Allah صلی اللہ علیہ وآلہ وسلم?” He said: “No, (I heard it) from the Messenger of Allah صلی اللہ علیہ وآلہ وسلم .“(Sahih).