I just purchased a set of used wheels that came with an unknown, hard, baked-on black stuff on the inside. Maybe tar mixed with other stuff. Is this Krud Kutter good for these types of things? Where is it available? TIA! Brandon '98 A4 '84 Urquattro >Did you try Krud Kutter? Best stuff I've EVER seen. >Michael Riebs >Grand Rapids, MI >'90 V8Q >'98 A6QA