Storage: Once your homemade sweet potato fries have cooled to room temperature, place them in an airtight container or a resealable plastic bag and store them in the fridge for up to 3-4 days. Make sure they’re spread out a bit so they don’t stick together. To reheat, just place in the oven at 375°F for 5 minutes or in a toaster oven. You can also reheat in the air fryer.