Well the brake dust coating on my recently acquired NB was so thick it look like a coat of flat black paint. I tried several products in conjunction with a tooth brush and they all failed to do an adequate job; i.e. repetition with little results and probably because of the thickness of the deposits.
... so I began to experiment with non-approved methods

and had only two failures, they are...
The brillo pad work well, although, yep you guessed it, removes the top paint coating. The CRC manifold cleaner worked but if you use too much it allowed the tooth brush to remove the top paint coating. I'll take pics of these failed experiments.
So we all know that the third time is the charm, right... after rummaging through the house for various household cleaners, I saw Lime Away, oh man, what would that do?
It was like giving me something dangerous to play with. Well to make the long story short, it cleaned the brake dust coating off and did not mar the paint coating in any way. It even cleaned out the brake dust pits.
I just applied some to the rim, waited no more than two minutes and went to work with my tooth brush; then rinsed it with the water hose. Some of the thicker and pitted areas required to 2-3 attempts, but it all came off.