Colored clothes should not be soaked for a long time, let alone soaked. Because dyeing is not absolutely colorfast, it does not mean that it will never fade after soaking for a period of time. Especially in washing liquid, alkaline surfactant will accelerate the fading. If the heavily polluted clothes need to be soaked for a long time, they should be picked up and turned intermittently, so that the falling dye can be diffused into the washing liquid to prevent the concentration of the falling dye from causing local pollution.

In addition, during the turnover interval of long-time soaking. The air in the clothes should be exhausted, so that it can be completely immersed in the liquid to prevent the color difference between the part below the liquid surface and the part above the liquid surface.