Through His own blood.

Hebrews 9:11-14, But when Christ appeared as a high priest of the good things to come, He entered through the greater and more perfect tabernacle, not made with hands, that is to say, not of this creation; and not through the blood of goats and calves, but through His own blood, He entered the holy place once for all, having obtained eternal redemption. For if the blood of goats and bulls and the ashes of a heifer sprinkling those who have been defiled, sanctify for the cleansing of the flesh, how much more will the blood of Christ, who through the eternal Spirit offered Himself without blemish to God, cleanse your conscience from dead works to serve the living God?

The world views this idea of cleansing blood as foolishness; to those being saved it is God’s amazing wisdom. We have access to His cleansing blood at every moment.

Cleanse my conscience by the power of Your blood that I may serve You, O Lord.