While we are all being extra careful to wash our hands and avoid touching eyes, nose and mouth, we may forget that dirty shoes can track germs and bacteria into our homes and offices. 3M offers a solution with its Nomad Matting. The anti-fungal matt acts as a vehicle for disinfectant, which is poured onto its surface. All that is needed is a thorough wipe of one's shoes before going indoors, says Nelson Fung Pak-on, supervisor of 3M's commercial care division. The United States company (established in Hong Kong in 1962) also produces an ammonia-based disinfectant that has fewer side-effects than bleach-based, or alcohol-based, products. Before using a disinfectant, make sure it will not cause the carpet to disintegrate or lose its colour, Mr Fung advises. Alcohol-based disinfectants can kill viruses, but the alcohol has to be regularly replaced (note that alcohol is flammable and can pose a risk). Bleach-based disinfectants can react to light and as a result lose some of their strength, Mr Fung cautions. Bleaches, too, should be replenished. In addition, bleach can be irritating to the skin and the respiratory system, and cause shoes to be especially slippery after wiping. Note that these disinfectants can also damage the finish of tiles and wood floors. And remember that the matt is a disinfector, and should be cleaned regularly to maintain its efficacy. Because the disinfectant matting is damp, it is a good idea to use a dry towel to wipe one's shoes after stepping on the Nomad mat. 'We do not want to kill the virus and have someone slip and injure himself,' Mr Fung says. He also advises people to use recommended chemical and disinfectant mixes (some mixes could, in fact, weaken the disinfecting process). Also, indiscriminate mixing of chemicals could be dangerous, and may cause an explosion or produce noxious fumes.