I was mainly asking due to the fact it's just a piece of glass, and that my scratch isn't even over the touchscreen part of it (it's up near the corner). I've heard of people using toothpaste and all kinds of chemical combinations, so I was wondering if anyone has tried anything like that before on an iPhone
I had a massive scratch on my 3GS years ago right down the middle of the screen. I used extremely fine sandpaper to sand it down then cerium oxide to buff it out. Looked great when it was done but took hours and obviously you have to be extremely careful!
Unfortunately there is no way to remove it as rich wood has already said, the scratch will be (at minimum) down to the oleophobic layer, and any attempt to remove it will result in removing the coating and making the problem worse.
Unfortunately your only options are to live with it or screen replacement.
I hate when I read these because it makes me want to respond.
Why didn't you buy a glass screen protector? Their a dime a dozen on eBay and Amazon. If we still had plastic film protectors I could see the point but glass protectors feel no different and can be had for under $10. It amazes me that people come here to complain about something that could be easily avoidable. Same goes for phone cases. If you rock your phone naked then why complain about dents and scratches?