Ans: The answer No, you can't sand wet wood with a belt sander. Wet deck sanding can be ineffective due to the very way how sanding works. When sanding, the raised portions and fiber from the wood comes off like dust because it's completely dry. But if we are past a certain degree according to the moisture meter, those fibers won't be that easy to come off. Even If you managed to sand it somehow, the stains wouldn't last long afterward.