I know it was mentioned but the Greased Lightning works very well in about 10 to 15 minutes for anything I have done. If you leave the aluminum in any solution too long it will turn a gray to blackish color. Do not use the Orange Greased Lighting. It will do nothing. Get the one in the yellow, black, and white bottle. The one that says 'wear gloves'.
If you get very good tape or I use flashing tape (a high grade tape used in molding and forming of fiberglass and carbon fiber) you can cut out patterns or logos and mask off sections of the part to stay the original color.
3 Phase Racing///Schumacher///Max Amps///TigerMoth Racing
Team Tekin ///FMC lipo chargers///Neu Motors///Multiplex
Real racers dont wear boxers.