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 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.