The towel hardens mainly because the calcium and magnesium ions free in the water combine with the soap to produce calcium and magnesium soap attached to the surface of the towel. To prevent towel hair is hard, besides often clean outside, ought to put towel in lye water pan boil 15 minutes (general 1.5 kilograms water adds soda ash 30 grams can, notice wants to immerse the towel completely in lye water), take out towel after boiling and rinse thoroughly with clear water.Towel surface greasy become sticky, because towel surface adhered to a lot of sweat, tears and other secretions. When clean the towel with slippery and greasy surface, besides can use above method besides, still can put towel in thick brine to boil or very hot wash.The natural conditions in which bacteria thrive are high temperatures and humidity, so towels should always be kept dry. But the toilet of a lot of families does not have a window, ventilated condition is poorer, want to keep towel clean so, should wash with soap everyday, hang in the sun next drying or air in ventilated place. Towels should also be boiled in salt water once a week. Soaking towels in water and then microwaving them is also an effective way to kill bacteria.