Answer:
I go in dry and come out wet. The longer I stay in the stronger my surroundings get.
Break me and I am better immediately set and harder to be broken again.
While you were folding a letter you got me. Usually you will do whatever it takes to avoid me but now you can't help but find me.
rub me and a genie might appear
I am in the past, never in the future. I don't exist, but have existed. I saw what you saw, and this is what I will ever see. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.