Machine polishing on paintwork is simply the mechanical removal of defects through surface abrasion. The process involves abrading the top layer to remove a microscopic amount. This in turn smooths out the defects such as small paint scratches, creating a flatter surface. This also causes light to bounce off in a more uniform direction, levelling the optical finish, making the surface appear deeper and shiner. Polishing then is a bit like exfoliating for your vehicle.