Popular Mechanics writes:
Scrub Down
Cars get dirty. But there's more than just dirt and rain spots clinging to your car's exterior. Airborne industrial pollutants, acid rain, dead bugs, tree sap and bird droppings can all degrade the paint. Modern car finishes are all covered with a clear coat to protect the pigmented main layer, but even this UV-resistant outer layer will last longer if you maintain it. Keep things clean and waxed to repel water and pollutants.
The same goes for your car's interior. That slimy patina of French fries, Big Gulp, sweat and dirt will eventually turn your interior into a primordial swamp. Shampoo the cloth seats to remove all that gunk. Now, forget what you think you know. There's nothing under your kitchen sink that's appropriate for washing or cleaning your car, except maybe the glass cleaner. Leave the dish detergent for the dishes, and use a proper car-washing solution. Clean the window glass last to catch all the oversprayed cleaning products.
Leather seats deserve a proper leather cleaner, followed by leather conditioner to replenish the skin's natural oils. Save the protectant for the dashboard. I strongly recommend against using protectant on the steering wheel and rubber pedals, because it can reduce your grip to dangerous levels.
Park in the shade while washing and waxing to prevent the heat of the sun from drying off the car and making water spots before you can dry them. Wet the surface beforehand to help dissolve the bug stains and loosen the dirt. Hose the salt and mud off the wheel wells and undercarriage.
Clean the wheels first to keep all the slop from getting on the bodywork. Rinse the wheels down, but wax them with the rest of the paint. Now you can wash the car all over with a lambswool wash mitt, drying it with chamois, terrycloth or microfiber towels. Save the diapers--they're too abrasive.
Read more: http://www.popularmechanics.com/cars/how-to/repair/4324365
