Sunan Ibn Majah
439
Hasan Sahih+3

It was narrated from Ibn 'Abbas that:The Messenger of Allah wiped his ears, putting his forefingers in his ears and wiping the back of them with his thumbs, so he wiped them inside and out

Hasan SahihAl-Albani
Hasan SahihMuhammad Fouad Abd al-Baqi