Ja'far bin Muhammad bin 'Ali جعفر بن محمد بن علي - الصادق · The Book of Purification

It was narrated from Umm Salamah that the Messenger of Allah (ﷺ) at (meat from) a shoulder, then Bilal came to him and he went out to pray, and he did not touch water.

"If it is menstrual blood then it is blood that is black and recognizable, so stop praying, and if it is other than that then perform Wudu', for it is just a vein."

"I heard Umm Qais bint Mihsan say that she asked the Messenger of Allah (ﷺ) about menstrual blood that gets on one's clothes. He said: 'Scratch it with a stick and wash it with water and lotus leaves.'"