In our culture today, self is the modus-operandi. It is from oneself that one acts. From oneself moral absolutes come. From oneself judgement is enacted. From oneself (insert problem).
Yet, we are made for charity. We are made to give ourselves away. No matter the depth of our sin and how far we have pushed away from our own true nature, gift of self can still manifest.
This my brothers and sisters is a key to evangelization. Use what is given you. Each person, no matter the depravity, has done something good for someone else (even if for spurious or nefarious motives). This is the glory of God shining through the darkness of sin. Point out the light!