I keep a duffel bag full of detailing supplies in the front trunk.
Meguiar's Gold Class Wheel brush, Absorber, Several Waffle weave towels, some Sonus Clay, Plexus, Acrylic SPritz, S100 Wax, Carnauba Spritz, 1Z Rubber care(tires), 1Z cockpit cleaner, Klasse VLRP(black plastic), NXT spray wax(wheels), Concours buffing towel.
and that's just what I take with me for my weekly visit to the coin operated wash place. I have a big Stanley tool box full of more brushes, waxes, polishes, protectants etc. oh and can't forget my Porter Cable polisher.
here's a nice pic of S100 Carnauba wax on Black