First of all, we need to prepare a clean basin, pour a proper amount of warm water, and keep the water temperature at about 40℃, and then soak the collar part of the clothes in warm water.
Soak for two or three minutes, then take it out and lay it flat on the edge of the basin. Then take a proper amount of salt and sprinkle it evenly on the soaked collar, and then drop a few drops of shampoo evenly.
Then rub the neckline of the clothes repeatedly with both hands and put them into the water in the basin for cleaning. At this time, we will find that the stubborn yellow stain has been cleaned, which is simple and labor-saving.
Because the sweat excreted by human body contains fat and protein, which is also the main cause of yellow stains on neckline, because it is not soluble in water, adding salt can slowly dissolve fat and protein in water, and shampoo has a very good cleaning effect on human fat and protein, so this method is simple but practical.