clean it with some warm water a mild soap
I'm pretty new to the chicken thing, but my guess is that it's the same treatment for that as it is for pasty butts and chicks
Any other information you could give would probably help the other more experienced chicken owners help ya out.
She might have a prolaspe. If so, that would need to be placed back in very gently and she would need to be kept in the dark a bit to keep her egg production down while she heals. Do you have a picture?