When I first started making soap (many years ago), I was suprised to learn that the base (or soapy component) for this chemistry experiment was first obtained from sacrificial ashes.
The passage below from the book of Numbers re- iterates the use of the ashes as part of the purification ritual.
What can make us clean? Is it the rituals we keep, the company we associate with or the internal climate of our minds?
The ashes of the sacrifice blessed by the priest were kept in a clean place for the water for impurity for the people.
I John 1:7 (NIV)
But if we walk in the light,
as he is in the light, we have fellowship with one another, and the blood of Jesus, his Son, purifies us from all
Psalm 51:7 (NIV)
7 Cleanse me with hyssop,and I will be clean;
wash me, and I will be whiter than snow.
Numbers 19:1-10 (ESV)
19 Now the Lord spoke to Moses and to Aaron, saying, 2 “This is the statute of the law that the Lord has commanded: Tell the people of Israel to bring you a red heifer without defect, in which there is no blemish, and on which a yoke has never come. 3 And you shall give it to Eleazar the priest, and it shall be taken outside the camp and slaughtered before him. 4 And Eleazar the priest shall take some of its blood with his finger, and sprinkle some of its blood toward the front of the tent of meeting seven times. 5 And the heifer shall be burned in his sight. Its skin, its flesh, and its blood, with its dung, shall be burned. 6 And the priest shall take cedarwood and hyssop and scarlet yarn, and throw them into the fire burning the heifer. 7 Then the priest shall wash his clothes and bathe his body in water, and afterward he may come into the camp. But the priest shall be unclean until evening. 8 The one who burns the heifer shall wash his clothes in water and bathe his body in water and shall be unclean until evening. 9 And a man who is clean shall gather up the ashes of the heifer and deposit them outside the camp in a clean place. And they shall be kept for the water for impurity for the congregation of the people of Israel; it is a sin offering. 10 And the one who gathers the ashes of the heifer shall wash his clothes and be unclean until evening. And this shall be a perpetual statute for the people of Israel, and for the stranger who sojourns among them.
* pics from pyxels.com