Kurabo has developed an ecology denim material "Earth Denim" using waste yarn produced during the manufacturing process, and with this material, deep dyeing is possible only with indigo dye.

The manufacturing method for "Earth Denim" is (1) collect waste yarn produced during the spinning process at each plant of the company and dye it, and then collect various waste materials (cotton waste, cut-off selvage and cutting wastage) produced during each process of denim weaving, dyeing and sewing, and (2) make that waste yarn and collected waste material into a near-cotton condition by opening it up, spin it again with raw cotton and dye it only with indigo dye.

With this method, it is possible to use only normal indigo dye to manufacture dark, deep-color denim without using sulfide dye, which is necessary for deep dyeing, because a part of the spun yarn is already colored. It is possible to produce various expressions such as tinges of red and green by dyeing waste yarn with any color.

Owing to the above mentioned characteristics, "Earth Denim" can suppress environmental loads through recycling waste materials and reducing CO₂ emissions and it requires no complicated water treatment as no sulfide dye is used.