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How to Clean and Disinfect a Thermometer

Woman disinfecting digital thermometer

How you clean and disinfect a thermometer depends on the type of thermometer you're using. Luckily, the supplies you need are probably already in your kitchen and medicine cabinets. Just follow these easy instructions.

How to Disinfect a Glass Oral Thermometer

Oral thermometers get exposed to a lot of germs, so plan to clean one before and after each use. Old-fashioned mercury glass thermometers are no longer recommended, but you can use one of these cleaning and disinfecting methods if you're still using one. However, it's best to replace it with a modern thermometer as soon as you're able.

Soap and Water Method

You will need:

  • Liquid soap and cool water
  • A bowl
  • Clean paper towels

Instructions:

  1. Wash the thermometer in a bowl of cool, soapy water.
  2. Rinse thoroughly in clean running water. Shake off the excess water, but it's not necessary to dry before using.
  3. Use the thermometer immediately and then repeat the process.
  4. Let the thermometer air dry on a clean paper towel before putting it away.

Rubbing Alcohol Method

You will need:

Instructions:

  1. Dip the cotton ball or pad in alcohol.
  2. Rub the ball or pad on the entire thermometer, taking special care with the tip.
  3. Rinse thoroughly under running water. You can shake off the excess water, but it's not necessary to dry before using.
  4. Use the thermometer immediately, and then repeat the disinfecting process, but don't rinse off the alcohol this time.
  5. Let the thermometer air dry on a clean paper towel before putting it back in its case.

Disinfecting a Digital Thermometer

Never immerse a digital thermometer in any liquid to clean it or you'll ruin the electronics. Use one of these methods instead.

Woman holding digital thermometer

Disinfecting With Alcohol

You will need:

  • 60% to 90% rubbing alcohol
  • Cotton balls or pads
  • Alternatively, an alcohol wipe
  • Microfiber towel
  • Clean water
  • Clean paper towel

Instructions:

  1. Wipe the digital display with the microfiber towel.
  2. Dip the cotton ball or pad in alcohol and squeeze out some of the excess, or use an alcohol wipe.
  3. Avoiding the digital display, wipe down the rest of the thermometer, paying special attention to the tip.
  4. Wipe off the alcohol using a cotton ball dipped in clean water.
  5. Use immediately, and then repeat the disinfecting process, except you don't need to wipe off the alcohol this time.
  6. Let the thermometer air dry on a clean paper towel before putting it back in its case.

Disinfecting With a Bleach Wipe

You will need:

  • A microfiber towel
  • A bleach wipe
  • Cotton ball or pad
  • Clean water
  • Clean paper towel

Instructions:

  1. Wipe the digital display clean with the microfiber towel.
  2. Avoiding the digital display, wipe the rest of the thermometer thoroughly with the bleach wipe.
  3. Wet the cotton ball in the water, squeeze out the excess, and wipe away the bleach.
  4. Use the thermometer immediately and then repeat the disinfecting process.
  5. Let the thermometer air dry on a clean paper towel before putting it away.

How to Clean a Rectal Thermometer

A rectal thermometer is typically used to take a baby's temperature, and it must be cleaned before and after each use. You can use the following cleaning method on a glass or digital thermometer, but take care not to immerse more than the tip of a digital thermometer in water.

You'll need:

  • Soap and cool water
  • 60% to 90% rubbing alcohol
  • Cotton balls
  • Paper towels

Instructions:

  1. Before use, dip the cotton ball in the alcohol, squeeze out the excess, and wipe the tip of the thermometer completely.
  2. Wait a few seconds for the alcohol to evaporate, and then take the child's temperature, inserting the tip no more than one inch.
  3. Afterward, clean the tip with soap and water to remove any fecal matter.
  4. Follow up with a final swabbing with alcohol and then let the thermometer air dry on a clean paper towel before storing it away.

How to Clean and Disinfect a Digital Ear Thermometer

The probe on a digital ear thermometer comes into contact with ear wax and germs. Not only can this become a source for infection, it can also interfere with the thermometer's accuracy, so regular cleaning is very necessary.

Medical ear thermometer

You will need:

  • Cotton swabs
  • 60% to 90% rubbing alcohol
  • A clean microfiber cloth

Instructions:

  1. Wet a swab with alcohol, and gently clean the thermometer's lens and probe first.
  2. Using a new swab dipped in alcohol, clean the rest of the thermometer.
  3. Wipe the body of the thermometer with the microfiber cloth.
  4. Use the thermometer immediately and then repeat the cleaning process.
  5. Once the unit is dry, store it in a safe place.
  6. Be sure to clean any accessories that came with the thermometer in the same way.

Cleaning a Non-Contact Forehead Thermometer

Non-contact forehead thermometers do not receive the same level of exposure to germs that contact thermometers do if they're used according to the directions. Disinfecting is typically not needed, but cleaning is still a good idea to keep the thermometer functioning as it should.

Non-contact forehead thermometer gun

You will need:

  • Cotton swab
  • Cotton pad or paper towel
  • 60% to 90% rubbing alcohol

Instructions:

  1. Dip the swab in alcohol.
  2. Carefully wipe the lens located in the probe.
  3. Wet the cotton pad or paper towel with a little alcohol and wipe the rest of the thermometer.
  4. Give the thermometer a few moments for the alcohol to evaporate, and then it's ready to use.

It's recommended that the lens be cleaned in this manner every two weeks. Do not use bleach or ammonia-based cleaners on the lens because they could leave a film that keeps the thermometer from working properly.

Using Hydrogen Peroxide on a Thermometer

You can use hydrogen peroxide to disinfect a clinical thermometer, but it will add some time to your routine.

You'll need:

Instructions:

  1. Wash the thermometer (just the tip of a digital thermometer) with soap and water, and rinse well.
  2. Pour enough hydrogen peroxide in a glass to cover the tip of the thermometer.
  3. Put the thermometer in the glass and let it soak for about 20 minutes.
  4. Lay the thermometer on a clean paper towel and let it air dry before storing it in its case.

Never Microwave or Boil a Clinical Thermometer

Of all the disinfecting methods you can use, you should never boil or microwave a clinical thermometer. The extreme heat generated by boiling can shatter a glass clinical thermometer, and even holding just the tip of a digital clinical thermometer in boiling water could allow the steam to get inside and obscure the display and damage the electronics. Similarly, microwaving can also ruin a thermometer due to the extreme heat, and it can cause severe damage to the battery in a digital thermometer.

Make the Extra Effort

Taking a temperature is relatively quick business and going to the trouble of cleaning and disinfecting your thermometer each time you use it will add extra minutes to the task. Even so, it's crucial that you do it kill bacteria and viruses like SARS and COVID-19, so think of your time and effort as an investment in your family's health and safety.

How to Clean and Disinfect a Thermometer