You can run the lenses under water for a minute, or you can use specialized cleaning solution designed for use with glasses. Window cleaning sprays also work well. Do not yet apply any chemical that contains abrasive materials or has a high acid content (as will be mentioned in later examples). Glasses typically have layers or coatings over the lens itself. As you are polishing or cleaning, you are really just wiping this exterior coating. When you remove scratches, you are buffing or removing a small amount of the exterior layers. It is best to keep this to a minimum in the initial phases of scratch removal.