I agree, the meguiars polish works like a champ on the rainbow scum on the black trim. That rainbow film/discoloration comes mostly from the "rainbow sealer" that's used at the automatic carwashes and compounded by the elements.

__________________
2022 X6///M - Toronto Red, Silverstone Full Merino Leather, Executive Package w/Remote Engine Start, Soft-close doors, Heated & Cooled Cupholders, Front Ventilated Seats, Front & Rear Heated Seats, Front Massaging Seats, Carbon Fiber Trim.

2002 X5 3.0i, Sport Premium, Titanium Silver, Grey Dakota, Cold Weather Pkg, Xenons, DICE, LED Tails, just a winter vehicle...

2007 550i, Sport Premium, Silver Grey Metallic, Grey Dakota, Nav, Cold Weather Pkg, Comfort Access, HD Radio, Xenons.