I start with an E, end with an E, and have a letter in me. What am I?

I am heavy forward, but backward I’m not. What am I?

I am black when you buy me, red when you use me, and gray when you throw me away. What am I?

I am full of holes but still hold water. What am I?

My rings are not worth much, but they tell my age. What am I?

I fly without wings. What am I?

The more you take away from me, the bigger I shall get. What am I?

I eat, I live. I breathe, I live. I drink, I die. What am I?

I sit in a corner while traveling around the world. What am I?

Tear me off and scratch my head, what once red is now black. What am I?