Good evening, unfortunately if the scratches are deep there's not much you can do to repair it. If they are minor however there is one thing you can try it's called, buff compound jewelers rouge.
I used to be in the glass business years ago and when we got small scratches in mirrors or glass we would use this to buff it out if they were not to deep a scatch. jewelers use this to buff stones with also. heres a link where you get get this, http://www.eastwood.com/ew-buff-compound-jewelers-rouge-18-oz-tube.html?utm_content=13137&utm_campaign=Shopzilla01&utm_source=Shopzilla&utm_medium=Merchant-Centre&SRCCODE=1SE1532
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