Overheat it. Excessive heat will damage vitamins and protein (ditto freezing). Heat in warm water for 10 minutes or so and remember that cold formula has yet to kill a baby. And while everyone’s done it from time to time, avoid the microwave.
Make your own recipes. Don’t think you’re smarter than Mead Johnson or Abbott, prepare formula as instructed. Adding less water, for example, to help your baby gain weight should only be done under the direction of a professional. The wrong mixture can lead to dangerous levels of minerals.
Let it sit. Prepared or opened infant formula should never be allowed to sit at room temperature for more than two hours. Sugar and warmth = growth of the weird and wonderful. In the fridge, formula is good for about 24 hours. When in doubt, throw it out.
Play roulette. Unless your baby has clear signs of milk protein allergy, there’s likely little to be gained from formula roulette. Gamble at will, but remember: Babies have symptoms for a reason and formula change is rarely the answer.
Dump it at the airline security gate. According to TSA breast milk and formula in quantities exceeding 3 ounces may be brought onboard and airplane so long as it is declared at the security checkpoint. And no, you don’t have to taste it in front of the TSA agent.