What product can I use to remove the scratches that are medium deep where I can see the white stuff underneath the paint?
Unfortunately, when it is that deep, the best thing you can try yourself may be various levels of buffing. You can do the coarse, medium, and fine buffing. Try buffing them out and try painting it over.
When they are that deep, odds are you are never going to get it to look right. Because either you are going to fill it with too much paint and have little mountains sticking up or it’s going to have a little valley inside. You are going to have a hard time blending them and matching the paint.
When they are really deep unfortunately, you’ve got to sand it down to the bare metal, all around, re-prime it, and re-paint it. That’s quite a job. You can try as best as you can to buff it and put a little touch-up paint, but it’s never going to look perfect. Because the paint won’t lay flat like it does when you spray paint on it. I’ve been there and done that.