Firstly, a very thorough jet-wash to get the surface grime off.
Then, I use Autoglym mousse:
https://www.autoglym.com/products/wh...leaning-mousse
... a bit expensive but quality product and the mousse sticks well to the wheel while doing it's business.
Then, use brushes of different sizes to get into the wheel without scratching the black lacquer.
Then a final jet-wash to get all the chemical off ... and a dry-off with a micro-fibre towel, and then some decent tyre seal.
Very satisfying if a little time-consuming!