I got a new car which is only few months old. I've clay with Mequiars' clay and polished with Autoglym Super Resin Polish. After that the paint surface felt smooth with bare fingers but i can feel some grittyness when using a plastic bag to test it. Please help or advise me if this is normal or do i have to use a separate paint cleaner (like Mequiars Medallion Premium Paint Cleaner). I really don't know what is wrong since the car is new and i've already done the claying.