Turtle wax wheel cleaner followed by a treatment of Turtle wax brake dust barrier or any car wax. (prevents the brake dust from sticking making them much easier to clean in future, usefull on BBS wheels like mine!)
When you are using the wheel cleaner spray it on and leave it for a minute, then use a paintbrush or wheel cleaning brush (not one you use for anything else!) to loosen the brake dust then rinse or powerwash off. Its a wise precaution to remove any plastic centre caps before using wheel cleaner, as it can discolour / damage any badges.
Went to local Tesco, or nearest anyway, they didnt have any wheel cleaner , but I did pick up 2 massive cans of Wheel/Bumper touchup spray and upholstery cleaner aswell as a new car smell magic tree for £3.50 which aint bad, I love tesco , Im just gonna try elbow grease tommorrow on my alloys with an alloy brush and a stronger mix of the wash/wax I use for the car.