How to clean this off wheels?

[slickooz]

My friend has these wheels that need some cleaning. What do I need to get these white stuff off these alloy wheels? It's been caked on for a long time I think.

 

[slickooz]

Anyone know what those white spots are and how to treat them?

 

[Indy YZF]

Looks like the aluminum is oxidizing. I'd try some metal polish if not clearcoated, but it's probably coated and is under the clear (try some M105?). Happens to almost every late 90's GM with clearcoated aluminum wheels (probably other brands, I've just seen a lot of GM wheels like that)

 

[BobbyG]

Those are signs of oxidation and if they're clear coated then it's failing and the only recourse is to refinish them or purchase new wheels..

 

[ScottB]

looks like clearcoat failure indeed ...