You might be able to buff up the marks, but you'll have a hard time getting the surface finish to match with the rest of the kit.
Try this first:
- use a pencil eraser and see if you can buff out some of the marks.
If that doesn't work, you're probably looking at 'painting'
- use a scouring pad (very fine) and rub the marks out
- coat with a primer. (this will fill in some of the finer scratches too)
- get a can of flat black paint and spray paint the model
Chances are that as you assemble the model, you will *ooze* some glue and make a few more scuff marks in other areas. You'll probably want to clean those up too, and maybe even touch up the 'seams' a bit. The advantage of 'painting' is that you can do all of that work and then cover it all up later. Spray cans are pretty easy to use and will go quite a long ways over several models.
Others may have better advice, though...
M.