I would just take it for a good drive at a decent clip for as long as I can manage. The brake cleaner will clean some of it. The rest it will liquefy and then it will run into crevices and cracks and crannies and might end up somewhere safe or somewhere worse.

Not sure what the alignment shop's concern regarding the parking brake is. The difference between engine on and off is the way the parking brake is applied. Hydraulically and using all four of the pads and rotors with the engine on or only the rear wheels via shoes internal the rear rotor hats or by a motor clamping the rear calipers with the engine off.

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8/2011 X5 xDrive35d Sport, Black Sapphire Metallic, Black Nevada Leather, Fine Burr Walnut Trim
2/2001 M5, Jet Black, Exclusive Complete Black Walk Nappa Point Heritage Leather, Black Cubic Trim