Yes, you can use Mod Podge to seal a wooden puzzle. To do this, apply a light coat of Mod Podge Puzzle Saver to the front of the completed puzzle and let it dry. Then, add a medium layer of the puzzle saver, letting it dry between coats. Once dry, you can mount the puzzle to foam core using Mod Podge, add a mat, and frame it for display. Mod Podge Puzzle Saver dries transparent, so your puzzle will be preserved and ready to showcase.