Bamboo is an eco-friendly, highly renewable source of material. The majority of today's bamboo flooring products originate in China and other portions of Asia where bamboo grows in abundance. Bamboo is a great choice for flooring because of its physical similarities to hardwoods. It is popular for its strength, durability, eco-friendliness and natural resistance to insects and moisture. Manufactured bamboo flooring is made by slicing mature bamboo stalks into strips. The outer skin and nodes are removed, and the strips are boiled in a solution of boric acid or lime to remove starch and sugars. Most bamboo flooring uses a Urea–formaldehyde (UF) resin adhesive in the lamination process. Bamboo flooring products that avoid formaldehyde use are also available, including some listed in the GreenSpec® Directory. The panels are then heat-pressed to cure the adhesive. The cured boards are planed, sanded and milled, and finally an ultraviolet curing lacquer is applied to the boards. Like most hardwood floors, bamboo floors should be treated carefully. It is best to use a dust mop before mopping to remove the dust and grime. A stiff bristled broom can be used to remove more stubborn dirt from the crevices of the floor. Wet mops should be avoided on the bamboo flooring. If it is necessary to mop the floor, be sure to wring the mop out thoroughly to prevent any extra water from being released onto the floor. Cleaning detergents should be checked to make sure that they are safe for hardwood flooring. Many soap products contain a waxing agent that will dull the color of the flooring and leave behind a filmy glaze. The US Green Building Council's LEED program offers points for the use of bamboo floors because it is a rapidly renewable resource.