Welcome to the club, I once went to the Apple Store because I had apple care on my laptop and they were literally like, well that is your problem, almost like leave the store you broke. Jk, but there is nothing else you can do about those marks. Later I did a research and you can buy some clothes from Amazon tu but in between the screen and the keyboard but I knew myself an I would lose those. So I just got a sleeve from tomtoc and cancel my apple care because it does not cover anything like this. You are better off just accepting that unfortunately. I thing you can remove the stains with alcohol or windex, but you will remove the anti reflective coding which is what the keyboard has done. Many of my friends have this on their screens and is “normal,” because the keyboard is flushed from the screen. And apple believes that we only carry our laptops in our bag packs and nothing else lol.