Use a spoon or your hands (if you're carving a jack-o-lantern) to remove the seeds and pulp from a pumpkin.
To clean the pumpkin seeds: While the pumpkin pulp is still wet on the seeds, place them in a bowl and cover with cold water. With your hands, swish the seeds around and remove any large bits of pulp (this softens the seeds and makes them easier to clean more completely). Drain into a colander, then continue rinsing until clean. To dry, spread the pumpkin seeds onto a clean kitchen towel or layer of paper towels. Pat very dry, changing the towels as needed.
To roast, preheat the oven to 300°F. Line a large, rimmed baking sheet with parchment paper.
Place the clean, dry seeds in a medium mixing bowl. Drizzle with the oil and honey. Sprinkle with the chili powder, garlic powder, and cinnamon or cayenne. Toss until the seeds are evenly coated, then spread them into an even layer on the prepared baking sheet, breaking apart any seeds that have stuck together.
Roast pumpkin seeds until they are light golden brown and fragrant, about 40 to 45 minutes, tossing every 15 minutes. Let cool and enjoy!
Notes
TO STORE: Store roasted pumpkin seeds in an airtight container at room temperature for up to 2 weeks, or in the refrigerator for up to 3 months.
TO REHEAT: Let the roasted pumpkin seeds come to room temperature before eating.
TO FREEZE: Place the seeds in a zip-top freezer bag or in an airtight container and freeze for up to 6 months.