Akoya pearl bleaching is a common, but generally undisclosed treatment used to even out the color in white cultured pearls. After the harvest, pearls are soaked and heated in a mild pearl cleaning solution under bright fluorescent lights. This results in a more uniform white color over all the pearls. It is also common practice to color enhance or dye the pearls following the bleaching process to add a subtle overtone. Dyeing takes place after the pearls are drilled and is sometimes detectable by examining the drill hole under magnification. Polishing and sometimes a coating complete the process. Pearl producers claim that it is the only economical process to create the matched strands of pearls that the market demands.