Can I use soapy water as clay bar lubricant?

Diluted car shampoo can work as a clay lubricant, but dedicated clay lubricants are designed to stay slick longer and not break down the clay. Some soaps and strong cleaners can degrade traditional clay, making it sticky or crumbly. Whatever you use, keep the surface very wet and the clay gliding freely; if it starts to grab or squeak, add more lubricant immediately.