Stop Using Baking Soda to Clean Your Washing Machine! Japanese Experts Reveal an Affordable Method That Flushes Out a Tank Full of Black Sludge, Making Years-Old Mold and Grime Float Right Up

As summer arrives, weather becomes unpredictable. If you happen to do laundry on a rainy day, clothes may not dry properly—and worse, your washing machine could become a breeding ground for mold. Many people use baking soda to clean their washing machines, but this practice is actually discouraged. Baking soda has low solubility and tends to form fine particles that settle at the bottom of the machine and in the drain. Japanese research indicates these residues can serve as nutrients for mold. In fact, washing machines used only two to three times a week are more prone to mold growth than those used daily.

This connection between usage frequency and bacterial levels was featured on the Japanese TV program "Mezamashi Television." In humid conditions, moisture builds up inside the machine, and leftover detergent provides nourishment for mold, creating an ideal environment for its proliferation. Studies have shown that washing machines used just two to three times a week contain over 13 times more mold than those used every day.

If mold grows inside your washing machine, it can contaminate clothes during the wash cycle. In severe cases, this may lead to skin issues such as eczema or dermatitis. According to the Indoor Air Quality Information Center under the Environmental Protection Department, mold is not a bacterium but a type of fungus—a microscopic organism that feeds on dead organic matter. Indoors, mold breaks down organic materials and can damage food, building materials, textiles, leather, and carpets.

Under suitable indoor conditions—such as the presence of nutrients (dead organic matter), appropriate temperature, and sufficient moisture—these microscopic mold spores germinate like seeds and grow into visible colonies. These colonies, known as "mold spots," can range from small (millimeter-sized) to large areas and appear in various colors, commonly green or black, but sometimes other hues.

Household appliance expert Yuki Wada advises opening the washing machine lid frequently during humid rainy seasons to ventilate and reduce mold growth. Additionally, she recommends regularly running the machine with a mixture of bleach and warm water to effectively kill mold.

Washing Machine Mold Removal Steps: - Remove the washing machine filter and clean off any debris. - Clear lint and residue from the drum’s interior surface. - Fill the machine with warm water (40°C to 50°C) up to the highest water level. - Add the recommended amount of chlorine bleach according to the manual. Run the machine for 5 minutes, then let it sit for 3 hours or longer. - Use a skimmer to remove floating black dirt. If you don’t have one, you can make a DIY version using an old hanger and a pair of pantyhose. - Run another rinse cycle with old towels or unused clothes. - After spinning, thoroughly wipe the inside of the drum to complete the process.

Note: This article is republished with permission from Hong Kong 01 (original title: Mold | Rainy Day Laundry Leads to Mold Explosion! Japanese Expert Shares One Highly Effective Anti-Mold and Disinfection Trick) Editor: Lin Li