Modern brake pads can tend to dust as the compromise of wear and braking power is engineered.
If you have the factory coated wheels, try a wheel cleaner like Mothers Foaming All Wheel & Tire Cleaner -- spray it on, let it set for 30 seconds or so (scrub a little if necessary) and hose off with a strong spray. Cleans tires real well, too!
If you have the factory coated wheels, try a wheel cleaner like Mothers Foaming All Wheel & Tire Cleaner -- spray it on, let it set for 30 seconds or so (scrub a little if necessary) and hose off with a strong spray. Cleans tires real well, too!