Quote Originally Posted by jmpet626 View Post
Don't use car shampoo as your lube it will degrade the clay. You can use optimum no rinse or DP Rinseless wash and gloss for a more economical product for your clay lube. IMO I don't like to bring my car to the car wash shops for claying since you don't know if they have already dropped the clay and they are just reusing it.
Yep, the surfactants in your car shampoo will degrade the plasticizers used in most clays. I've read that the non-Clay Magic clay (those illegal to sell in the US, like the poly-clays from Riccardo and Optimum, as well as some clays such as those sold in the UK by Bilt Hamber, AutoBrite, and some Dodo Juice Clays), don't break down even when used with car soap; not planning on testing mine though .

Add as well that they'll wash the car both before and possibly after claying; and unfortunately, the wash procedure of most car washes (even the more popular ones) just aren't up to par with regards to minimizing swirls and marring in your finish. So you might get marring from clay that's been used too long or being applied to aggressively, and you'll also get more swirls and scratches from improper car washing techniques.