Place between 1 and 3 tablespoons of cornstarch in a bowl. If you see any lumps, use the back of a spoon to crush them or mash them with a fork. If you want a light starch, just use 1 tablespoon. If you want a heavy starch, use 3 tablespoons.
Add 2 cups of cold water to the cornstarch and use a fork to vigorously stir the mixture until the mixture has no lumps.
Use a funnel to pour the mixture into a spray bottle. Replace the pump and screw it tightly. When you use the spray to iron garments or other objects, shake the bottle and spray the fabric. Let it rest for 30 seconds before ironing it to allow the cornstarch to penetrate the fabric so that you won't have a white, powdery finish on the cloth. Use the steam setting on the iron to create the crispest finish.