I know you lads have been using Bar Keepers Friend for ages, but it saved my day while detailing uncleaned year old Merc alloys yesterday. I did not use it on the outside clearcoat, just the internal rim and hard to reach inner rim. Mixed with my usual degreaser/cleaner and a rough microfibre to a watery paste the brake dust came out no problem. Combined with Sonus extra fine detail clay even the stubborn areas around the valve came out like new. Could not find any trace of scratches afterwards either, but still did not risk it on the outer alloy. Finished off all wheels with a x2 coat of Rejex. To do all 4 wheels without rushing and stoping for dinner took 6hrs.