To clean a thermometer safely, wipe the probe or tip with rubbing alcohol (at least 60–70% isopropyl) or soap and water after every use, then let it air dry completely.

How to Clean a Thermometer

Quick Scoop

  • Clean before and after every use to avoid spreading germs.
  • Use 70% isopropyl alcohol or alcohol wipes for most home thermometers.
  • Never immerse electronic/digital units fully in water or harsh chemicals.

Step-by-step: Digital Thermometer

  1. Initial rinse
    • Rinse just the metal/plastic tip under cool or lukewarm running water to remove residue.
 * Avoid getting the display, buttons, or battery compartment wet.
  1. Wash
    • Clean the tip with mild liquid soap and water using your fingers or a soft cloth.
  1. Disinfect
    • Wipe the probe with a cotton pad or cloth soaked in 70% isopropyl alcohol, or use alcohol wipes.
 * Focus on the area that contacts the mouth, armpit, or rectum.
  1. Rinse (optional, except rectal)
    • Some guides suggest rinsing off alcohol for oral/axillary thermometers; always follow the manufacturer’s instructions.
  1. Dry and store
    • Let it air dry on a clean paper towel or dry with a soft, clean cloth, then store in its case.

If the thermometer is used rectally, wash with soap and water first to remove any stool, then disinfect with alcohol and let it air dry before storing.

Glass (Non‑mercury) Thermometer

  • Wash the entire thermometer in a bowl of cool, soapy water; avoid hot water to prevent damage.
  • Rinse thoroughly under clean running water.
  • Disinfect with an alcohol-soaked cotton ball or pad, then either rinse again or let the alcohol evaporate, following the product’s directions.
  • Air dry on a clean paper towel before putting it away.

If yours contains mercury and breaks, do not clean it yourself; contact local health or environmental authorities for safe mercury spill guidance.

Infrared / Non‑contact Thermometers

  • Use a soft, lint‑free cloth lightly dampened with alcohol (around 70% isopropyl) to wipe the lens area and outer surface.
  • Do not scratch the lens, use abrasive cleaners, or immerse the device in liquid.
  • Allow it to air dry fully before next use or storage.

Safety Tips & When to Replace

  • Do not use bleach directly on most digital or infrared thermometers unless the manufacturer specifically allows it, as liquid can enter and damage electronics.
  • If the thermometer is cracked, discolored, or giving inconsistent readings even after a fresh battery and proper cleaning, replace it.

TL;DR: Clean the tip with soap and water, then disinfect with 70% alcohol after each use, keep water away from electronic parts, and let it dry completely before storing.

Information gathered from public forums or data available on the internet and portrayed here.