While washers rarely stain clothes, a stain could appear due to a substance like beverage, food, cooking oils, medicines, or hair care products getting oxidised during the wash and becoming visible.
Identify the source of the stain to ensure clothes washed later aren’t stained. Some common causes of staining might be - fabric softeners, rust or mildew present in machines.
Another crucial step in identifying the source of stains is observing any patterns such as - the location of the stain, number of clothes stained, clustered stains, pinched stains, coloured stains or occurrence of soil transfer.