Preheat oven to 375ºF.
Rinse the seeds in a bowl of water, separating as much of the of stringy squash pieces.
Add the seeds to a pot, size dependent on how many seeds you're cooking. Add enough water to cover the seeds.
Bring to a boil over medium-high heat. Reduce to a vigorous simmer, and cook for 5 minutes, Strain seeds from water. Add to a towel, and rub off excess water.
Line a rimmed sheet pan with parchment paper. Scatter seeds on pan. Add a drizzle of olive oil, sea salt, and spices, if using. Spread seeds into a single layer.
Roast for 10 minutes, stir and spread back into a single layer, Roast for 10 to 15 minutes more, until seeds are dry and crisp.