Seeing as how you've already screwed it up, you may as well try the suggestions I always post in these scratched monitor threads that everyone never comments on favorably or negatively.
They make a "space age polymer" liquid for repairing scratches in eyeglasses. It is a liquid that goes on like clear nail polish and is supposed to fill the scratches and harden clear. In the commercial for it, they scratch up the lenses with sandpaper, then repair it to look good as new.
I think they may sell this stuff at Walgreens now. I'm sure if you did a Google for eyeglasses and scratch repair you'll find something and might be able to read some reviews of people who have tried it. Dunno if it would work for surface scratches on a picture tube, but it's worth a shot if your tube is looking bad.