Hadith 8:2139
Abu Bakr narrated to us, he said: Ibn ‘Ulayyah narrated to us, from Yunus, from al-Hasan, that he used to like to refrain during the ten [days of Dhu al-Hijjah] from [cutting] his hair and his nails. And he did not see any harm in the oven.
حدثنا أبو بكر قال حدثنا بن علية عن يونس عن الحسن أنه كان يحب أن يكف في العشر عن شعره وأظفاره وكان لا يرى بالتنور بأسا