I assume plastic frames is what has been scratched. Deep ones forget it. Light scratches try something like Duroglit crome/silver cleaning paste or pads. I used to clean mine in my last house with that and they came up quite well for a while then had to do them again. Alternative is to contact a local window supplier and ask them if they have any type of cleaner that would suit subject to the scratches being too deep.
However if your talking the glass how did that get scratched?. You can't it's a replacement job.
