Purity: Removing Impurities Before Ghusl
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 552:
If there is an intrinsic impurity on any part of a corpse, it must be removed before ghusl is given to that part; and it is better to remove impurities from the entire body before starting the ghusl.
-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)