Zaynab bint Umm Salama reported,

I heard my mother Umm Salama, the wife of the Prophet ﷺ, say, "A woman came to the Messenger of Allah ﷺ and said, 'Messenger of Allah, my daughter's husband has died, and her eyes are causing her pain. May she apply kohl to them?'"The Messenger of Allah ﷺ replied, "No," two or three times, each time saying, "No." Then he said, "It is only four months and ten days. In the days of ignorance, one of you would throw a piece of dung at the end of a year."Humayd said, "I asked Zaynab, 'What does throwing the dung at the end of a year mean?'"Zaynab replied, "When a woman's husband died, she would enter a small, wretched hut and wear her worst clothes. She would not touch perfume or anything else until a year had passed. Then an animal would be brought to her, a donkey, a sheep, or a bird, and she would rub herself with it to break her state of mourning. Rarely did she rub herself against anything without it dying. Then she would come out, and a piece of dung would be given to her, which she would throw away. After that, she could return to using perfume or whatever else she wished."(And this is the third of them.)

عن زينب قالت

سمعت أمي أم سلمة زوج النبي ﷺ تقول: جاءت امرأة إلى رسول الله ﷺ فقالت: يا رسول الله. إن ابنتي توفي عنها زوجها. وقد اشتكت عينيها. أفتكحلهما؟ فقال رسول الله ﷺ: لامرتين أو ثلاثا كل ذلك يقول: لا ثم قال: إنما هي أربعة أشهر وعشرا. وقد كانت إحداكن في الجاهلية ترمي بالبعرة على رأس الحول قال حميد: فقلت لزينب: وما ترمي البعرة على رأس الحول؟ فقالت زينب: كانت المرأة إذا توفي عنها زوجها. دخلت حفشا ولبست شر ثيابها. ولم تمس طيبا ولا شيئا حتى تمر بها سنة، ثم تؤتى بدابة، حمار أو شاة أو طير، فتفتض به، فقلما تفتض بشيء إلا مات، ثم تخرج، فتعطى بعرة فترمي بها، ثم تراجع بعد ما شاءت من طيب أو غيره. (وهذا ثالثها)