A cave stands near the entrance of Aqua Auto Spa. Cars approach slowly, their drivers peering into its dark recesses. Inside, soft cloths burnish vehicle exteriors in a matter of minutes, making them as a shiny as the sun’s mouthful of braces. All washes come with free use of the self-serve vacuums, plus complimentary glass cleaner, wipe-down towels, and dash dusters. Nearby, an industrial washing basin brims with towels, brushes, and grooming shears. Here, dog owners can lather pups’ fur with canine shampoo or style it into a handsome pompadour.