Medium what am I riddles

I get whiter the dirtier I get. What am I?

I am something to make you think, I am something to make you know. I am something to which the answer you might never know. What am I?

You can easily touch me, but not see me. You can throw me out, but not away. What am I?

When you have me more, you can see only less. What Am I?

I build up castles. I tear down mountains. I make some men blind, I help others to see. What am I?

A slender body, a tiny eye, no matter what happens, I never cry. What am I?

My best buddy always makes mistakes. But I would easily get rid of the mistakes. What Am I?

I look taller when I am young. But as I get old, I become shorter and shorter. What Am I?

I am only useful when I am full, yet I am always full of holes. What am I?

I am a fruit. Remove my first letter, it's a crime. Remove my first and last letter, it's a kind of music. What do you think am I?