Like kwacker said, I used a .22 rifle barrel cleaning kit once which has a couple of different hard long brushes which was ideal as they would not cause any damage to the internals along with a bit of Mr Muscle limescale cleaner. Also try one of these old fashined hardware stores, I found one (Hurst's) in Newport IOW that had the same thing for only a £1. I woudn't use coathanger as could damage the internals