I may have used a bit too gritty sand paper initially... I'm now using 1500 and 2000 grit wet dry. Any way, I have some scratches that aren't coming out with the 1500 and 2000 on the black sparkle part of my boat. It just seems that the super fine paper, 1500 and 2000, aren't really doing enough.

What can I do to get them to go away?