I use Tamiya Extra Thin and never bothered to clean or sand excess glue marks on tank models. Tanks are supposed to look dirty. However, I assume that I’d better sand excess glue marks on Formula One car models because glossy paints will reveal such marks. Am I correct? I want my F1 cars look clean.
Yep. Body prep is key to a good paint job.
Agreed. You may have to use a couple of grades of sandpaper. A coarser grade, sometimes, to cut into the glue marks, and then a finer grade- maybe even two, to get rid of the scratches. And, primer is a big aid. I always prime before painting to ensure I have gotten rid of all scratches, glue marks, unfilled seams, etc.