I know you're into your "slag" look mate -- and on most topics I completely agree with you (although personally I'd say things in a different... less blunt manner) but that's possibly the worst approach you can take to washing a car! Cheaper car shampoo's and stuff you find in the "cupboard" are generally harmful to the paintwork and contain harmful detergents! And as for sponges (I occasionally do use them) but I try to use my lambswool mit because the dirt gets caught deep inside the fibres and drawn away from the paintwork rather than trapped on the surface of the sponge scratching the surface as you wash! I use autoglym or meguiars -- 2 bucket wash, then polish to bring it up and then a good coat of wax to protect it until the next proper wash (which these wintery days may be every fortnight)