My infant is so dirty that I want to leave her out on the rain.
In the rain? Why not just give her a good wipe down?
Because she was so dirty.
I think that a bath might be a better idea. You should not leave a child outside, especially in the cold rain.
It is not just to get her clean. It is also just for kicks, I'd like to see her how she reacts.
Well I don't think she will have a good reaction to being left outside in the cold rain. And CPS will probably not have a good reaction to knowing that you left her out in the rain. Your child will get taken away if you do that.