I soaked the pants overnight in water with a dash of vinegar.
Into the crockpot: 5 cups water. 4 packages lemonade koolaid. 40 drops of yellow food colouring. Mix well, add wet pants. Cook on low until dye is exhausted, which took 2 hours.
Allow to cool in the crockpock. This took several hours. The results were a little splotchy, but that's okay.
Now, on the stove, in the top of a double broiler: 2 cups water. 2 packages strawberry koolaid. Using the gradated dying tutorial, slowly dye the pants bottom to top.
Cool. Rinse. Dry flat. Voila! Volcano pants!