The guilt of our sin is humanly impossible to blot out. It is indelible. It can stick to you permanently, forever. Adopt all means within your power, and still, your guilt and your sin will remain.
Many have attempted to wash themselves clean with the lye of religious deeds and may have duped themselves into thinking that they are now clean. But to God, they are as filthy and defiled as ever.
Some have tried to wash themselves clean with the soap of reformation, philanthropy, good works etc., and have deceived themselves into thinking that they are now fine and okay with God, when the reality is that, still, in God's eyes, their guilt and their sin remain.
Nothing will do except the precious blood of the Lord Jesus Christ, shed on Calvary's cross.
1 Jo 1:7 ...the blood of Jesus Christ His Son cleanses us from all sin.
The moment we entrust ourselves to Him for cleansing, relying and depending on Him alone and what He did on the cross, is the very moment that our guilt, our sin and our stains are washed away.