Answer:
I am perfect with a head perfect without a head; Perfect with a tail perfect without a tail; Perfect with either neither or both.
You can read me both ways I wear; One way it's a number reversed a snare.
You will always find me in the past. I can be created in the present, but the future can never taint me. What am I?
I go through a door but never go in and never come out.
I have an eye, but I can't see. I usually have to work with something in my eye. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.