Actually. It's not being dirty that causes acne. It's better to wash your face than to not wash it, but in reality, dirt doesn't cause acne. And sometimes scrubbing your face can make acne worse.
I'm sorry, it just bothers me when people say this, because last year when my acne was really bad my friend told me that it was because I was too dirty. When I showered every single day and washed my face twice a day. She was dirtier than me, she just hadn't hit puberty yet. And now she has a face full of zits, so HA. Sorry. I'm still bitter about that >=(