Erm, rouge? Jeweller's rouge, or do you have to apply make-up??? I should think that polishing out scratches like this might lead to so much distortion as to be counter-productive. Might a better bet be something to fill in or disguise the scratches, like you can get for car windscreens? It might even be better to replace the glass....
Re. the glass scraper, I got one from my local hardware shop (a good "we stock everything" one) - one of the metal kind of scrapers with a retractable blade that takes single-edged razor blades. It's really good, much better than the Stanley knife bladed "DIY" versions - my old one vanished ages ago, and I've been looking for one for some time. Got 30% off a box of blades, too! Result! It's almost as easy to paint a window, not worrying about paint on the glass, and whizz off the excess when dry, as it is to do a proper job and run a paint bead along the glass.
J.B.