Hail damage and the blonde,

A blond was driving home after a game and got caught in a really bad hailstorm.
Her car was covered with dents, so the next day she took it to a repair shop. The shop owner saw that she was a blond, so he decided to have some fun.
He told her to go home and blow into the tailpipe really hard, and all the dents would pop out.
So, the blond went home, got down on her hands and knees and started blowing into her tailpipe. Nothing happened. So she blew a little harder, and still nothing happened.
Her blond roommate saw her and asked, "What are you doing?" The first blond told her how the repairman had instructed her to blow into the tail pipe in order to get all the dents to pop out.
The roommate rolled her eyes and said, "Uh, like hello! You need to roll up the windows first.."