taken from autopia and detailingworld.co.uk
http://www.guidetodetailing.com/article ... rticleId=9
Regardless of how gentle your car shampoo is, or when you last waxed your car, driving and washing deplete the wax or sealant protection you've applied to your car. For this reason, I like to use a quick detailing spray on my car after washing. A good detailing spray renews the just waxed shine and extends the life of your wax or sealant.
I will repeat a point I made earlier on another thread, polishes are abbrassive they remove oxidisation/swirls/surface defects by removing very small very fine layers of the laquer surface of the paint, they WILL remove wax and they will remove some of the top layer to the paint (which is not neccessarily actually paint). Polishes should also be removed after use so they don't keep removing layers, therefore polish does not build up.
Wax dulls and wears even over a period of days, washing the car will also strip the wax layer, maybe not all but some of it and possibly all of it, you just can't tell.
your comment is confused a good shampoo won't strip anything off the paint, but the wax layer is not part of the paint and I never said it was. I'll see if I can find a picture of the layers to describe what I'm hashing an explanation of!
325i Tech 1 Touring, breaking.
2.5 high comp. M20, 3.64 LSD, Fully undersealed, Spax springs & Bilstein shocks, s/s exhaust, Alpina rep wheels and more.