Corn syrup paint, looks like stain glass. Corn syrup and food coloring dries shiny..... We use this at my daycare and the kids love it!!!! stained glass lesson.
If you need a super simple volcano recipe, it doesn't get much easier than this. Prep is about 3 minutes, and there is no clean up necessary. Easy Baking Soda and Vinegar Volcano Eruption for Kids by Preschool Inspirations