Board Thread:Questions and answers/@comment-35749367-20180604212630/@comment-27306930-20180605040307

You're probably seeing some of the black plastic rail clip sloughing off onto the edges of the rail itself. It's kind of like paint transfer when you tap someone's car bumper.

I have had very good luck with 90% isopropyl rubbing alcohol. It gets off most scuff marks and paint streaks. Works best with cotton rounds - the kind your mother or sister uses to remove makeup.

Beyond that, you could try a little acetone. And I mean a little. Usually fingernail polish remover has just enough acetone in it to loosen the top layer of the ABS plastic shell. Wipe it on carefully with a paper towel, then wipe off any residue once the mark comes off. You might want to practice on an inconspicuous part of the blaster first.

Good luck !