To keep puzzle pieces from ending up on the wrong box, label both the box and the back of all its pieces with a designated letter (A, F, etc.) so that you can quickly identify which pieces go with which puzzle.
A Tip for Storing Outdoor Toys
To keep water and mosquitoes from collecting on the inside of outdoor toys, try hanging them in a net. Mesh laundry bags also work well, and can be hung under porches roofs or on the side of a fence.