As per my discussion with someone today, in my opinion a paint brush is the best type of brush to use when cleaning the Crossfire's interior, whether the car's leather surfaces or the dash/doors and center console. Nylon brushes, both machine or hand-held, are just too coarse and aggressive, and even a rag can remove too much of the delicate factory interior paint. But cutting down the bristles of a paint brush only to the point of adding enough stiffness to allow the ends of the bristles to be used for light agitation, is the best tool I've found for cleaning delicate surfaces without damaging or simply removing them. Used in conjunction with a MILD leather cleaner it's the only way I've found to effectively deep-clean my Vanilla interior surfaces.

On the left is a brush like you can buy at any store. On the right is my sorry attempt to cut a brush's bristles straight across!! Go ahead, I probably deserve to be laughed at. When you cut them with scissors the bristles try to "escape" so it's hard to get a straight cut. Perhaps someone can figure out a solution to that.