Cool Crispy Air Fryer Pumpkin Seeds (Ready in 15 Minutes) completely before sealing them. Keep them in an airtight glass jar at room temperature for 7 days. For longer storage, refrigerate the jar for up to 14 days. You can also freeze the seeds in a pressed-flat freezer bag for 3 months. Remove as much air as possible before sealing because oxygen makes the oil taste stale. Reheat a single layer at 300°F for 3 to 4 minutes and shake once halfway through. Let the seeds stand uncovered for 1 minute so the shells firm again. Don't microwave them because the centers warm before the shells recover their crunch. Discard seeds with a paint-like oil smell, visible moisture or a soft leathery bite. Any fuzzy growth means the whole batch should go.