Narrated Ali ibn Abu Talib: The woman who has a prolonged flow of blood should wash herself every day when her menstrual period is over and take a woollen cloth greased with fat or oil (to tie over the private parts).
Explanation & Benefits
Shaykh Umar Farooq Saeedi
302. Commentary:
Some scholars hold this view, and it is the statement of Ali (radi Allahu anhu), but it is not a marfu‘ (attributed to the Prophet sallallahu alayhi wa sallam) hadith, and even that is weak in its chain of narration. It is apparent that this situation is not obligatory; rather, it is recommended and desirable as a matter of cleanliness. Al-‘Allamah Mundhiri has described it as “gharib” (unfamiliar/rare).
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 302