i clayed my car when i bought it, it was pretty good, not much at all, so i was happy.
detailed the car today fully, interior, carpet, floormats,under the car, exhaust tip,dressed bumperettes and windshield thing by windshield wipers with back to black, tires, wheel wells,leather, polished the car with meguiars products with random orbital, and sealed with zaino. love the final results, it was never better looking.
but just take a look at what the claybar looked like after i was done
so no matter how clean you think your car is, think again.