It's not all about shining but also roughing up the other side of the ball. On most club decks balls can be shined pretty easily but the trick to getting late swing is the rough side. I have sometimes found that getting a ball wrecked on both sides, picking a side to shine and soaking the ball in sweat creates sharp swing. I've also noticed when a lands in a puddle outside the boundary, maybe on the covers for example, it get's soaked one side and reverses for a few balls. It's all about creating an imbalance in the ball either in weight or condition, enough to get it moving in the air. Work just as hard on that rough side!