novus novus 1-2-3 polish works wonders--get it and some lint free cloth the dangerous way is to melt it smooth.....DONT DO THIS!!!!!
I had a tiny scratch in the acrylic door on my case - I managed to successfully polish it out use T-Cut colour restorer for car paintwork. Just be gentle and only use a tiny amount.
Don't quote me on this, but I think that the toothpaste trick only works on really small/light scrathes. And it actually just more fills in the scratches so they aren't as noticeable. I don't think it actually removes or polishes out the scratch. Novus is definitely the way to go.