1. Pre-heat your oven to 200 degrees and line a baking sheet with foil.
2. Clean the pine cones before you put them in the oven with warm water and white vinegar, making sure they are fully submerged for 30 minutes, stirring half way through. The pine cones will then close up in the water.
3. Shake off the excess and pop them in the oven to bake for approximately 90 minutes, but keep checking on them to make sure they don’t burn. As soon as the pine cones have opened up again, then they are ready to be removed from the oven.
4. Then leave out to cool and fully dry before you use them for your creative masterpiece.