Washing handkerchiefs in hot water—specifically at 60 °C (140 °F)—may be more effective at killing germs than washing them in cooler water, according to a recent report. Many people opt to wash their handkerchiefs at lower temperatures, such as 30 °C (86 °F), thinking it is better for the environment. However, this method may not fully eliminate viruses and bacteria, as the mechanical action of the washing machine alone is not enough to destroy these pathogens. At 30 °C, the washing process can remove visible dirt and mucus, but it does not break down the protective envelopes of viruses like those that cause the common cold or flu. These envelopes are made of proteins and lipids, which remain intact at lower temperatures. As a result, germs may remain in the fabric and could potentially re-infect the user when the handkerchief is used again. Additionally, washing contaminated handkerchiefs with other clothing at low temperatures can spread germs to other items during the wash cycle. To effectively kill most bacteria, viruses, and staphylococci, the report recommends washing handkerchiefs at a minimum of 60 °C for at least 30 minutes. This temperature is crucial because it helps destroy infectious agents. However, only 100% cotton handkerchiefs can handle repeated high-temperature washes without damage, as synthetic blends may shrink or wear out at this temperature. If using high heat is not an option, adding sodium percarbonate—a type of oxygen-based bleach—can help improve the sanitizing effect of the wash. However, heat remains the most effective way to kill germs. Other methods of sanitization include using a steam iron, which can reach over 100 °C (212 °F), or a tumble dryer on a cotton cycle, which provides dry heat and reduces humidity, helping to prevent bacterial growth. Proper handling before washing is also important. Handkerchiefs that are damp or crumpled should not be left to sit for long periods, as this can encourage bacterial growth. If someone is sick, a dedicated washing cycle should be done within 24 to 48 hours. Using a washing bag can help keep handkerchiefs separate from other towels, reducing the risk of cross-contamination. Following these steps—washing at 60 °C, using 100% cotton, and washing quickly after illness—can significantly improve the hygiene of handkerchiefs.