My Dad recommended a cleaner/polish called 210. It's made for the isinglass on boat biminis and he has used it for years. He said it will help prevent minor scratching, after you've used it a few times. It's a polish so it builds up a protective barrier and it's also supposed to help with the windows fogging (which happens here in the FL humidity). I used it for the first time today and so far am really pleased with it.