Ok here’s what you do. Make sure that the lid and the rim of the paint can don’t have any crude on them. Then knock the lid on real tight. If you use a hammer be sure not the bend any of the metal. A rubber mallet is better suited for this. Now just turn the paint can over and the paint will seal it self in the can. It is as simple as that. If your kids are anything like mine then don’t store it in the house. You’ll walk around the corner to find your little sweetheart is the next Picasso. I keep mine in the garage. The down side to that is the extreme hot and cold will shorten the life of the paint.