Is there a product I could use to remove the scratches in the screen of my W810i? Or materials I should avoid using to clean the nasty sweat off of my phone when I/other people use it? It has a couple of tiny scratches that you can only see when the screen is off and at a certain angle, but I know that they're there.

 

You could try Plexus. Get a jewelers cloth or one for glasses and spray a little on the cloth.