How do I became aware of it, I do not know - but last year in front of the Winter I ordered a bottle and have now when changing tires the old (former Winter made not clean) wheels first cleaned. According to one inscription clean wash (that have spraying with one per Pressure Washer done), then let the spray cleaners and act a bit and then with a strong jet of water (again my Pressure Washer) it a little rough. Lo and behold ... suddenly the color of the rims ... silver! I was very taken aback, because I've never seen in any product so a good effect.
My wheels were indeed so dirty that I repeated the application again (inside - outside an application was sufficient) - but that I did not even even in the vicinity of the rims with the brush, the effect was far better than Andren funds with a brush :-)