Our fairly new dodger has spots all over the windshield. It looks like water droplets have dried on it and left a stain. They don't come off with just a sponge and water, which is what the maker of the dodger told me to do. A friend suggested using microfiber cloth and water. Is that safe to use or will it leave a scratch? Would Simple Green be good to use ?

I have a spray can of Plexus but it seems I should try to get the spots off before adding something that might lock in the stains.

Thanks,
Max