Expensive due to the duty, but it IS the best you can buy
I tried this product in a 17 oz spray on a Porsche Carrera and was so impressed, I reordered it in the gallon size.  I'd had stubborn baked-on brake dust on the inside of my rims that I hadn't been able to totally remove in two years, having tried at least a half-dozen products.  Sonax was successful on it's first try.  Being so obscure and unable to locate it anywhere but on Amazon, I decided to bite the bullet and splurge for a case.  You just never know when it might go out of circulation.  Now I'm set for a very long time.  Get it now while you can!
Rating: 5 stars