I find that some of the vehicles I encounter have browning and embedded mud or fine soil that doesn't come out with pressure washing or scrubbing. I have used Simple Green and Megs APC in the past with great results (Even after washing the SG will suck the crap and mud out of the tires), but I don't want to continually subject aluminum rims to the Simple Green. Is there something that is just as effective but safe to use on aluminum? ARO? Thanks.