Carefully wash pumpkin seeds to remove all excess pulp. Transfer pumpkin seeds to a paper towel–lined rimmed baking sheet. Allow to rest at room temperature until completely dry, about 1 hour. To speed up the process, dry pumpkin seeds in a 200 degrees F (90 degrees C) oven, stirring occasionally, or use a hair dryer. Adjust oven rack to center position and preheat oven to 325 degrees F (160 degrees C). In a large bowl, toss dried pumpkin seeds with oil and season with salt and pepper. Transfer to a rimmed baking sheet. Roast until pale golden brown, stirring occasionally, about 25 minutes total.
