I rencently purchased a used vehicle and I noticed that on the drivers side of the windshield, there is small scratches from the wiper blades either not being changed or sand getting under the blades and they were used on dry glass. I would really love to get these scratches out and make the glass clear again. I am hoping that this product will work for my needs as I do not want to have to take it in and pay hundreds of dollars. So I would like to know how difficult this product is to use.