We do stone chips all the time. We have the customer get the touch-up paint from the dealer. Then we use a heavy tooth pick to apply it. The wood of the pick absorbs the paint, than when we put a little presure on it, it squeezez out a little paint at a time. Put the paint on a little higher than the surrounding painted surface. Let it dry, sand it down so it is level and polish out the scratches you created by sanding. Before we start we tell the customer that it won't be 100% but it's way better than the chip. When we are done most times you would never know there was a chip. Sometimes if you really look you can see it, but again it's way better than before