Oh it is the old dung heap covered in snow analogy. Here's the Catholic one. A sinful soul is like a silver plate covered with tarnish. God does not simply cover the tarnished plate with a cloth. He removes the tarnish, cleans it all off, and washes the soul so clean of sin that when he looks at the polished plate the only thing he sees is his own reflection.
Beautiful. I'll take being the reflection of God, washed clean of the grime of sin, over being a dungheap covered in snow, any day.