So my friend rode my fixie with a rear brake on my back wheel, which is a non-machined Deep V. Having never rode a fixie, and subscribing to the general front-brake phobia, he left black streaks on my Deep V. I'd been meaning to remove the rear brake because of its lack of use, but alas, too late, before it marked my rim.

So I was wondering if there's any good way to clean off rubber marks from a aluminum rim. I've tried rubbing alcohol with no avail, and tried Gorilla tape (which takes off almost any adhesive), also with no avail.

Any ideas?