Al-Harith bin al-Azma' narrates that he heard Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) say: "Whoever is in a state of major ritual impurity (junub) and bathes with khitmi (a soap-like plant) has done enough."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9222