How to Clean a Thermometer Safely: Prevent Germs and Cross-Contamination at Home

If you’ve ever reached for the family thermometer in a moment of panic—maybe your toddler woke up flushed or your aging parent felt a little off—you probably didn’t stop to think about the last time it was cleaned. Most of us don’t.

But thermometers are one of the few personal care tools that come into close contact with the mouth, skin, or underarm—places where bacteria and viruses love to linger. If that same device is passed from one family member to another without proper cleaning, those invisible germs can travel, too.

In homes with children, older adults, or anyone with a weakened immune system, those small lapses in hygiene can have big consequences. That’s why understanding how to clean a thermometer safely—and when a single-use option is the better choice—is a small but powerful way to protect your household’s health.

Let’s dive into five important points to keep in mind when cleaning your home thermometer, so you can stop germs from spreading while keeping temperature checks safe, accurate, and stress-free.

1. Common Mistakes When Cleaning Thermometers

Most parents and caregivers know that thermometers should be cleaned—but how and when are often overlooked. A few of the most common mistakes include:

• Skipping cleaning altogether. Many people simply return the thermometer to its case after use, assuming it looks “clean enough.”
• Wiping with tissues or dry cloths. This doesn’t kill germs that can survive for hours or even days on plastic and silicone surfaces.
• Using water or harsh chemicals. Submerging a digital thermometer can damage the internal electronics, while bleach or abrasive cleaners can erode the sensor tip.
• Forgetting to clean between family members. Sharing the same thermometer for multiple kids—or between kids and adults—without disinfecting it in between increases the chance of germ transfer.
• Storing it in warm, moist places like bathrooms. Humidity encourages bacteria to multiply, turning a “clean” thermometer into a hidden germ hub.

Nurse’s tip: Even if your thermometer looks spotless, it could still carry pathogens capable of causing illness.

2. How Germs Survive and Spread Through Shared Devices

It’s easy to underestimate how long germs can live on everyday items, but research shows that many bacteria and viruses can survive on hard surfaces like plastic, glass, and silicone for longer than you think—hours, days, weeks, even months. Yes, months! That means your family thermometer, remote controls, and even light switches can quietly collect and transfer microbes from one person to another.

When you take a temperature, the thermometer often touches skin, saliva, or mucus membranes—areas that can carry germs. If that same device is used again without cleaning, it can move those germs to the next person who uses it. This is especially important in homes with children, who may touch their mouths or noses often, or in families caring for older adults or anyone with a weaker immune system.

Even if everyone in the home appears healthy, germs such as Staphylococcus aureus (MRSA), E. coli, and norovirus can spread silently through shared devices. That’s why infection control shouldn’t stop at wiping counters or washing dishes—it includes the health tools you rely on most.

Nurse’s tip: A shared thermometer is like a doorknob during cold season—it’s touched by everyone and can quietly pass along germs if it’s not disinfected.

3. Hand Hygiene: Your First Line of Defense

If there’s one habit that can make the biggest difference in stopping germ spread, it’s handwashing. Simple, yes—but still one of the most effective forms of infection control, both in hospitals and at home.

Every time you check a temperature, prepare a meal, help a child blow their nose, or assist an older adult, your hands collect bacteria and viruses from the surfaces and people around you. Without realizing it, you can transfer those germs to others—or right back to yourself.

The Centers for Disease Control and Prevention (CDC) recommends washing your hands with soap and water for at least 20 seconds, especially:

• After using the bathroom or changing diapers
• Before eating or handling food
• After coughing, sneezing, or blowing your nose
• After caring for someone who is sick
• Before and after checking a temperature or giving medications

If soap and water aren’t available, an alcohol-based hand sanitizer (at least 60% alcohol) can help reduce most germs in the short term.

When it comes to thermometers, handwashing before and after use is just as important as cleaning the device itself. Otherwise, you risk re-contaminating a freshly disinfected thermometer the moment you touch it.

Nurse’s tip: Think of it this way—your thermometer can only be as clean as your hands.

4. Safe Cleaning Practices for Reusable Thermometers

Even the best thermometer can harbor germs if it’s not cleaned properly. While cleaning routines vary slightly depending on the type of thermometer you use—oral, rectal, or underarm—the same basic principles apply.

Follow these steps to safely clean a reusable thermometer:

• Check the manufacturer’s instructions first. Some thermometers have delicate sensors or electronic components that can be damaged by certain cleaning agents.
• Disinfect after every use. Wipe the probe and handle thoroughly with a cloth or cotton pad soaked in 70% isopropyl alcohol. This concentration is ideal—it kills bacteria and viruses without corroding the thermometer’s surface.
• Avoid submerging it in water. Immersing the device, even partially, can ruin internal electronics or battery compartments.
• Let it air dry completely before storing it. Moisture left behind can encourage bacterial growth.
• Store in a clean, dry place. Avoid bathrooms or kitchens where humidity and aerosols from toilets or cooking can contaminate the device.

If multiple people in your home share a thermometer, disinfect it between each use and consider labeling it by site—oral, rectal, or axillary (underarm)—to avoid cross-contamination.

For families with infants, immunocompromised loved ones, or elderly parents, even small lapses in cleaning can pose risks. That’s where single-use thermometers offer a reassuring alternative—no cleaning needed, no waiting for devices to dry, and no chance of germs lingering between uses.

Nurse’s tip: If you’re using a reusable thermometer while caring for multiple family members, it’s safer to designate one thermometer per person whenever possible—or switch to a single-use option for peace of mind.

5. When Single-Use Thermometers Make Sense

Even with the most diligent cleaning routine, reusable thermometers can still carry risk. Studies have shown that shared medical devices—especially those used on multiple patients or family members—can harbor bacteria like MRSA, C. difficile, and Candida auris if not properly disinfected between uses. For hospitals, this risk has prompted stricter infection-control protocols. At home, however, those same precautions can be difficult to maintain day after day.

Why single-use makes sense:

• Zero cross-contamination risk. Each thermometer is individually wrapped and used once, eliminating the chance of transferring germs between family members.
• Clinically accurate results. NexTemp® and TraxIt® thermometers are built with liquid crystal technology validated in clinical settings. In studies, they’ve shown accuracy equivalent to mercury thermometers—the long-time clinical standard—without the safety hazards.
• No cleaning or reprocessing required. There’s no need for disinfectants, drying time, or special storage; simply use, read, and dispose.
• Ideal for families, caregivers, and travel. Whether you’re checking a fever in a sick child, caring for an aging parent, or managing health in shared spaces, single-use options combine hospital-grade precision with home-friendly simplicity.

For parents, this means faster decisions and fewer worries about sanitation. For caregivers, it means protecting vulnerable loved ones—without adding another cleaning task to an already full plate.

Nurse’s tip: Infection prevention isn’t just for hospitals. It’s something every household can practice—one small, thoughtful choice at a time.

FAQs

How should I clean a reusable thermometer?

Use 70% isopropyl alcohol or a disinfectant wipe after every use. Wipe the entire probe, not just the tip, and allow it to air dry completely before storing. Avoid submerging the thermometer in water or cleaning solution.

Can thermometers spread germs?

Yes—especially if used on multiple people without proper cleaning. Shared thermometers have been linked to the spread of bacteria and viruses in healthcare settings, and the same risk exists at home if cleaning is inconsistent.

How often should I wash my hands when taking temperatures?

Before and after every temperature check. Hands are one of the most common ways germs transfer between surfaces and people, so frequent washing—especially after bathroom use, cooking, or handling tissues—is essential.

Are single-use thermometers really more hygienic?

Absolutely. Each NexTemp® or TraxIt® thermometer is individually wrapped and used once, which removes the need for cleaning and completely eliminates cross-contamination risk between family members.

What’s the safest thermometer for families?

For multi-person households or caregivers monitoring both kids and older adults, single-use thermometers offer the best combination of accuracy, convenience, and infection control—no batteries, probe covers, or cleaning required.