Musannaf Ibn Abi Shaybah

Hazrat Umm Salamah and Hazrat Umm Habibah (may Allah be pleased with them) narrate that once a woman came to the service of the Prophet ﷺ and said that her daughter's husband had passed away. Her daughter had pain in her eye and wanted to apply kohl. The Messenger of Allah ﷺ said: Among you, when a year was completed, she would throw a camel's dung; now the waiting period is four months and ten days. Hazrat Humaid (may Allah be pleased with him), the narrator, says that I asked Hazrat Zainab bint Umm Salamah (may Allah be pleased with her) what is meant by throwing a camel's dung? She replied that in the age of ignorance, after a woman's husband died, she would sit in the worst room, staying there for a year. When the year was completed, she would come out and throw a camel's dung behind her.