Ben, you can polish a machined lip definitely. Depends how it is finished of course.
Do not use turps, or dish washing liquid on your wheels. Dish Washing liquid is ethanol based, and clearly you know what turps is! haha.
Use a proper wheel cleaner, 1Z Colourtec, All wheel Cleaner from Duragloss, Autobrite Wheel Cleaner are all safe for 2/3 piece custom wheels & matt wheels.
Cheers
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