So I recently acquired a set of black anodized wheels for a great price. The only problem was that they had been sitting under a birds nest and are covered in bird crap. I got the front wheel clean after lots if scrubbing but the rear wheel just won't come clean. I have tried using 409 cleaner but it doesn't do a whole lot. Any ideas on how to loosen the crap without taking off the anodization? Any advice would be greatly appreciated. Thanks