I use National Products alloy wheel cleaner to clean the alloys-but a word of caution-it's very strong and very aggressive. It'll shift the brake dust with ease-however i n=don't leave it on for long. I've never (touches wood) done any damage, but just be careful as some claim it can attack lacquer and paint. I have a mate who sells alloys to all the car accessory/Halfords type outlets-he has a nes A3 with 20" alloys on it- and he says he would never use anything but soap and water on he's wheels! I use it on all our VAG's- we have both original and aftermarket wheels and have never had a problem, but i wouldn't want a finger pointing at me. It's about £14 for 5 litres, thats mega strength. If you dilute it 50/50 with water it's still about the most powerful i've ever used-literally spray on rinse off. It's available from most good automotive refinishing factors. I think its called National Products-they do rubber clenz also for dressing your tyres etc, and polishes/glass cleaners etc. It's what a lot of car valet and car sales companys use. Much less expensive than buying 325ml/500ml wonder wheels at £7-£8 a time.Cheers. Paul