I started out with a piece of plastic that was once part of the packaging for a laptop hard drive (you can use anything similar and it doesn't have to be clear like mine), into which I cut a slot at one end to fit the car's guide flag. To use it, hold the car upside-down and slide it under the braids as in the picture:
You can now use either a brush or cloth soaked with your favourite cleaning liquid (I use isopropyl alcohol) to clean the contact surface of the braids without spreading any of the residue all over your car. Be sure to only stroke from the front to the back to avoid messing up the braids.
