Make a decoction by boiling 1 part of Catechu, Cutch, or Gambier in 30 parts of water, to which add a little soda. Apply this to the wood which is to be stained, and allow it to dry in the air. Make a solution of 1 part of bichromate of potash and 30 parts of water, and apply over the stain, which may be varied in color according to the strength of the solutions used. Catechu, which is much used in dyeing and staining, is the extract of the wood of the Acacia Catechu, the seeds of the Areca Catechu, and the leaves of the Nauclea Gambir. The Acacia Catechu is a small spiny tree, rarely exceeding twenty feet in height, the wood is hard and heavy, the center is of a very dark red color nearly approaching to black, it is from this portion of the wood that the extract is made. In India, it is made by the poorer natives, who move from place to place, selecting jungles where the Acacia is most abundant. They cut down the trees, and chop the heart-wood into chips, which they boil in water, when the water is deeply colored, it is strained off and submitted to the process of evaporation, fresh supplies of the decoction being added until the whole becomes sufficiently thickened by evaporation. It is then poured into clay moulds and left to dry in the sun.

The Catechu made from the Acacia Catechu is also called Cutch and Terra Japonica. The term Cutch is said to be named from the native language, in which the substance is called Kutt. Commercially, one variety is called Catechu, and another Cutch, although the source is the same. The former has been poured out onto mats when about the consistence of honey and dried in the sun. When sufficiently hardened, it is cut into small square pieces, and, after being thoroughly dried, it is packed into cane baskets for exportation. This variety has a light chocolate-brown color, and the cubes are about an inch square, having an earthy fracture and external appearance. The other variety, Cutch, is of a darker color, rich brown, with a shining appearance and fracture, it comes much mixed with broken leaves, in which it has been laid to dry, it is packed in a similar manner to the Catechu, but is most generally run into one mass. Gambier, or Gambir, is an extract of the leaves of the Nauclea Gam-bir, this plant belongs to the natural order of the Cinchonas, or Jesuits' bark trees. It is made by boiling the leaves and evaporating the decoction to dryness, in appearance it resembles Cutch, but it is not so glossy in its fracture, and rather lighter in color.

It is mostly imported from Singapore, where it is extensively cultivated.