If you find a coin, carefully remove it and check for other warning signs like scratches, broken glass, or missing items. Focus on real security risks: don’t leave valuables in sight, store your key fob in a signal-blocking pouch, and consider using steering wheel locks or dashcams. In the end, a penny in your door handle is likely harmless — but it’s a reminder to remain vigilant and protect your vehicle with smart, modern safety habits.