To stop people reading un-necessarily , this is a question about alloy wheels on a Nissan, nothing ot do with space, life the universe or anything else!

A year ago, I bought a car. A Nissan sunny. Link to pictures. I'll state that it hasn't given me any real trouble except one section of the exhaust developed a hole and had to be replaced.

You may notice, if you look at the pictures, it has alloy wheels. Now I've never had a car with alloy wheels before and they are starting to look pretty shabby. I washed the car this afternoon, and scrubbed the wheels several times. The mud and road crud comes off easily enough as does the fallout from the brakes.

What remains are a variable number, more on the front then the back, of stubborn black spots, each about 10mm in diameter.

Do any car oriented people here know how to remove these marks?

I'd considered a wire brush or wool, but the surface of the wheels looks smooth with some kind of finish on it, I guess wire wool would remove the marks, but possibly open that area up to worse.

<rant - don't read>
When I lived in England, I'd go to Halfords and they tell me what to do and had just the right stuff.

Here, any problem with a car and you take it to the garage who then charge you an absolute fortune to tell you what you need to do, and then tell you they can't sell you the stuff because you need to be a registered car wheel cleaner or something stupid, which of course costs a fortune to become. So you have to book it in for a minimum charge, then materials then VAT at 25% plus "environmental tax" which varies depending on the season, phase of the moon, mood of the garage ownerŽ. You end up with splendid wheels, a delighted garage owner, and a sadly depleted bank account.
</rant>