if u really want to learn how to clean a car properly i read a 363 page article on autopia-carcare.com by one of the most renound professional cleaners who does car's before car shows inside and out, engine and undercarriage.
Read it. learn about products, steps in the order in which you should clean, and a shit load of other stuff about using the right stuff in the right places.
as a result my 1994 camry i have with a new paint job looks brand new daily and only wear on it is some slight wrinkles in the leather but ressembles that of a 2000 + leather.
Mike-