Read Jeremiah 2:21-24.

"For though thou wash thee with nitre, and take thee much soap, yet thine iniquity is marked before me, saith the Lord God" (v. 22).

A former Colgate Palmolive soap factory employee relates that although there are newer processes for making soap, the essentials are more or less the same as when made on the farm from soda ash and the lard rendered from a pig. The raw ingredients to make soap are oils – palm oil, coconut oil, or even fish oil; for bar soap, caustic soda or lye from soda ash; and for soft soap, caustic potassium from potash.
These ingredients are boiled in huge vats. After the vats are cooled, and the chemical reaction results are removed, it is necessary to clean the vats, which are heated by huge, coal-fired boilers. The soot must be cleaned from the horizontal six-foot-high pipes leading to the chimney stacks. The unfortunate part of this process is that even though you have a lot of soap available, you can not get clean. At the end of the two weeks, it takes to clean the pipes, the employees have to throw their clothes into the garbage. After many showers, they still don’t look clean. They bare stains that even soft soap won’t clean!
We face the same problem. We have many remedies for cleaning up our lives that have been fabricated by man. We have seminars, AA meetings, NA meetings, self-help books, support groups, and therapy sessions, but even though these methods may give temporary relief, none of them can remove the stain of sin. Only the atoning blood of Jesus Christ can cleanse the stain of sin from the heart and life of a repentant individual who believes in the Son of God for salvation. (Gayle Woods)
Only the atoning blood of Jesus Christ can cleanse the stain of sin.