Have you ever rushed out of your car, leaving something important behind? We’ve all been there. Between running errands, commuting to work, and driving kids around, our cars often become a second home filled with all kinds of stuff. But while your vehicle might seem like a convenient storage space, there are certain items that should never be left inside. The temperature inside a parked car can climb to over 100 degrees on a 70-degree day in just 30 minutes, and during winter, it can drop well below freezing. These extreme conditions can damage your belongings, attract thieves, or even create safety hazards.
Medications can become ineffective or dangerous
That bottle of pills in your glove compartment might seem harmless, but extreme temperatures can change how medications work. Heat, cold, and humidity can alter the chemical composition of many medications, making them less effective or even harmful. Insulin, for example, can degrade in hot temperatures, while other medications might lose potency or develop toxic compounds. Even over-the-counter medicines like pain relievers aren’t immune to temperature damage. The plastic containers can also leach chemicals into the medications when exposed to heat.
If you need to carry medications while traveling, consider using a insulated medication travel case to help maintain a stable temperature. For daily use, take your medications with you rather than storing them in the car. The cost of replacing damaged medications can add up quickly, especially for prescriptions not fully covered by insurance. More importantly, using compromised medications could put your health at risk. If you suspect your medication has been exposed to extreme temperatures for an extended period, check with your pharmacist about whether it’s still safe to use.
Electronics don’t like extreme temperatures
Leaving your laptop, phone, or other electronics in your car is asking for trouble. High temperatures can damage batteries, causing them to leak or even explode. The liquid crystal displays (LCDs) found in most devices can also be damaged by heat, leading to dark spots or complete failure. Cold weather isn’t much better for electronics – batteries can drain faster in cold conditions, and condensation can form inside devices when bringing them from cold to warm environments, potentially causing short circuits.
Beyond the damage from temperature extremes, electronics left visible in cars are prime targets for thieves. Even if your car is locked, a determined thief can break a window in seconds if they spot valuable items inside. The cost of replacing a broken window often exceeds $300, not counting the value of stolen items. If you must leave electronics in your car temporarily, store them in the trunk before reaching your destination. Better yet, take them with you whenever possible. For longer trips, consider bringing a padded electronics case that provides some insulation against temperature changes.
Valuable items attract unwanted attention
Purses, wallets, shopping bags, and other valuables should never be left in plain sight in your vehicle. These items are like magnets for thieves, who often look for quick grab-and-go opportunities. Even if your car is parked in what seems like a safe area, it only takes seconds for someone to smash a window and grab your belongings. Many car break-ins are crimes of opportunity, meaning thieves are looking for easy targets. Visible valuables make your car an obvious choice compared to one with nothing in sight.
Identity theft adds another layer of risk when personal items are stolen from cars. Your purse or wallet likely contains credit cards, ID, and possibly your Social Security card or other sensitive information. Recovering from identity theft can take months or even years, causing significant stress and financial hardship. If you need to leave items in your car, use a car trunk organizer to keep everything out of sight. As a general rule, treat your car like a fishbowl – assume everything inside is visible to passersby. The best practice is to take valuable items with you or lock them in the trunk before arriving at your destination.
Aerosol cans might become dangerous projectiles
Those seemingly innocent spray cans of hairspray, deodorant, or air freshener can become hazardous when left in a hot car. Most aerosol cans contain compressed gases that expand when heated. When temperatures rise inside your vehicle, the pressure inside these cans increases dramatically. If the pressure exceeds what the can was designed to withstand, it can rupture or explode. An exploding aerosol can isn’t just dangerous to your car’s interior – it can cause serious injuries if you happen to be nearby when it bursts.
Many aerosol products also contain flammable propellants like butane or propane. When these substances leak from an overheated can, they can create a fire hazard inside your vehicle. The risk increases if there’s any source of ignition, such as electrical sparks from car components. To stay safe, never leave aerosol products in your car, especially during hot weather. If you need to carry these items, store them in a cool, shaded area of your vehicle temporarily, and remove them when you reach your destination. Consider switching to non-aerosol alternatives like non-aerosol toiletries for products you frequently carry in your car.
Important documents should stay protected
Your car is not a filing cabinet for important paperwork. Birth certificates, passports, Social Security cards, and other important documents should never be stored in your vehicle. These items are incredibly valuable to identity thieves and extremely difficult to replace if stolen. The cost of replacing a passport alone can exceed $100, not counting the hassle and time required to get a new one. Beyond the risk of theft, paper documents can be damaged by heat, cold, and humidity in your car.
If you absolutely must carry important documents while traveling, keep them on your person rather than leaving them in your vehicle. For everyday needs, only carry copies of documents when possible, leaving originals in a secure location at home. Consider using a waterproof document holder for added protection from unexpected spills or weather. Remember that replacing stolen identity documents often requires other forms of ID, creating a frustrating catch-22 situation if multiple items are stolen simultaneously. A small fireproof and waterproof box at home is a much better storage solution for these critical papers.
Bottled water isn’t always refreshing
Keeping a case of bottled water in your car might seem like good emergency preparedness, but those plastic bottles can cause problems when exposed to heat. When plastic water bottles sit in a hot car, chemicals from the plastic can leach into the water. Studies have found that heat accelerates the release of chemicals like antimony and bisphenol A (BPA) from plastic into water. While research on health effects continues, many experts recommend avoiding these chemicals when possible. The taste of the water can also change, developing an unpleasant plastic flavor after being heated.
Plastic bottles can also act as magnifying glasses in direct sunlight, potentially focusing light and heat to the point where they could start a fire. Though rare, there have been documented cases of this phenomenon. Additionally, water expands when it freezes, which can cause bottles to crack or burst in freezing temperatures. If you want to keep emergency water in your vehicle, consider using a stainless steel water bottle instead of plastic. These bottles are more durable, won’t leach chemicals, and can better withstand temperature extremes. For longer trips, bring fresh water each day rather than storing it in your vehicle.
Sunscreen needs proper storage
Keeping sunscreen in your car for spontaneous outdoor activities seems smart, but heat can break down the active ingredients, making it less effective at protecting your skin. Most sunscreen manufacturers recommend storing their products at temperatures below 77°F (25°C). When left in a hot car, sunscreen can easily be exposed to temperatures well above 100°F, causing the protective compounds to degrade rapidly. The consistency of the product can also change, becoming runny or separated. You might not notice these changes until you’ve already spent hours in the sun, thinking you were protected.
Using degraded sunscreen gives a false sense of security that can lead to painful sunburns and increased risk of skin damage. Considering that skin cancer is the most common form of cancer in the United States, proper sun protection isn’t something to compromise on. Instead of storing sunscreen in your car, keep it in a cool bag or cooler if you’re heading out for the day. Many companies now make travel size sunscreen that’s easy to carry in a purse or backpack. Remember that even water-resistant sunscreen needs to be reapplied regularly, so keeping it with you rather than in your car makes regular application more convenient.
Your car is designed for transportation, not storage. What you leave behind might not survive the temperature extremes or could attract unwanted attention from thieves. Take a moment when exiting your vehicle to gather important items, especially during extreme weather conditions. This simple habit can save you money, protect your belongings, and even prevent dangerous situations. By being mindful about what you leave in your car, you’ll avoid unnecessary replacement costs and keep your valuable items safe for years to come.
