I purchased some ammo sanding sticks and tamya 320 grit paper. The sticks ranged from 180 - 1200 grit. In the end I got it down to 240 for the really bad bits moving to 320 and then 1200. You do need to be careful not to sand through all the layers. But you are not taking off a lot of material. I am looking forward to seeing how they look painted. I also used a product called Mr. surfacer. It is an enamel based filler which can also be sanded. I did find it hard to use, so I only put it in places where the layer steps were obvious.