How can I clean brake dust off my wheels?

I clean my car every month but I have noticed that there has been a steady build up of some small hard spots of brake material on the wheels that is very difficult to remove, even with a pressure washer. The dust is easily washed off. I have tried most of the readily available products including BMW's own, but soaking and using a small brush is very time consuming and not very successful. Have you any ideas or magic tips or products you could suggest?
You need to clean the black brake dust off regularly because it is partially metallic and highly corrosive. There are wheel-cleaning sprays by people like Autoglym and Meguiars, but they are a bit acidic and you then have to wash the wheels very thoroughly of any residue. I use an old toothbrush to agitate the dirt.
Answered by Honest John on

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