Clayed my car and scratched the hell out of it


Okay, I need a littled advice here. I washed my car this weekend and then rolled it into the garage for an application of WGDGP. However, I felt a couple of panels and decided that it needed a clay first. I clayed the hood, roof and trunck and then i had to go run an errand. I came back to my car and noticed that I scratched the hell out of the finish. Not bad scratches but none the less it took about 2 passes with the M205.

What did I do wrong? I am fairly certain that the car was clean. Was the clay old and full of contaminents? It was bright blue but it was old. I am not a detailers, it's just a hobby for me? The clay was Megs medium grade, is that too harsh? Or, was I not using the clay lube right?

I have no idea and could use a little help.