Steel wool pad (0000 grade) with some glass cleaner, followed by a wipe-down, then clay bar, another wipe-down. I added a base carnuba cleaner wax (yes I waxed my glass) and the wipers have been quiet and smooth ever since.

Did this to my girls e46 as well as she had noisy Bosch Icons. Also solved the issue, and keeps the water off while driving in the rain.

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8/06 build E53 3.0i....