Invisible Shield questions

It really doesn't matter. Clean the ipod first. How well you want to do that is up to you. My advise would be to get it as clean as possible before putting the invisible shield on since it will be there for years. But only buy the scratch remover stuff if you think it will work. I'm not sure in that area. Just be sure to get in a well lighted area and don't rush the process. It can take some time. Depending on the ipod also i've had to cut a little piece out of the shield on the corners. Spray a lot of the soap water stuff they give you and then squeegee out from the middle once its aligned. On edges or corners that you cant get to stay down, just keep rubbing every few minutes while you watch a tv show or something and it should stay down.