Time for fall. Pinecones!To clean pine cones, soak them in a solution of warm water and white vinegar, typically a 2:1 water-to-vinegar ratio, for about 30 minutes to kill bugs and remove dirt, then rinse and dry thoroughly, often followed by baking at low heat (around 200°F) to open them and melt sap. Some crafters also use a little dish soap or bleach, but vinegar is a popular. After you can paint them for fall decorations and Christmas Ornaments with acrylic paints with kids.