let us draw near with a sincere heart in full assurance of faith, having our hearts sprinkled to cleanse us from a guilty conscience and our bodies washed with pure water. — Hebrews 10:22

Having our hearts sprinkled clean from an evil conscience — that's what Christ's blood does. The old covenant sacrifices could only cleanse the flesh externally, but Christ entered the holy place once for all. His blood speaks a better word than abel's, and in him we have redemption and forgiveness according to the riches of his grace. Your conscience can be clean because his work is finished.