Preheat the oven to 400°F. Grease a rimmed baking sheet with the vegetable oil.Melt the unsalted butter in a small pan over medium heat. Add the sugar, cinnamon, ginger, cayenne, cloves, nutmeg and salt. Stir to combine.Add the pepitas to a medium bowl and add the butter spice mixture. Toss to combine well.Spread out evenly on the prepared baking sheet and bake for 15 minutes. Stir once or twice during the baking process to make sure they brown evenly. Let cool completely.