Really? Thats *clean*? Wow... the car must have been missing the inner wheel well trim or something to get that much road debris. Or maybe a CV axle failed and they never bothered to clean off the grease. Or both.
Anyway, I'm sure I can get it cleaned up a bit more if I soak it in something that is aluminum-friendly and then brush it off. Since I'm not going for a show car it doesn't have to be spotless so its all good.
Thanks for the feedback and if I do another swap in the future I'll get in touch