I just set up a booth and borrowed a sand blaster from a friend to deal with asphalt in my fender wells. Why? Because paint will not stick to it. Not cheap paint like rustoleum or spendy 2 part epoxy primer I've tried both. It will look ok untill you hit it with a pressure washer or comppressed air and then it will lift like a page of paper. I've tried grinding, sanding, carb cleaner and reducer but that s*#t gets deep into the metal and won't let go. The sand blaster is doing the job great and is at least as fast as grinding and sanding and I won't have to worry about paint failure inside the fenders anymore. Just a warning as you start to dig it out that covering it up with paint won't make you happy down the road
